My Brother’s Great Invention | CBSE Class 7 English Notes

This note covers the story "My Brother’s Great Invention": its summary, characters, themes and style, the margin words, the grammar, and answers to the textbook tasks.

What is "My Brother’s Great Invention" about?

About the text

"My Brother’s Great Invention" is a humorous story by Anita Rau Badami. It is the first piece in Unit 3, Dreams and Discoveries, of Poorvi, the English textbook for Grade 7. The other two pieces in the unit are the poem "Paper Boats" and "North, South, East, West".

About the Book, at the front of the textbook, says the unit captures the wonder and imagination of children and sparks curiosity and creativity. It calls the story a humorous tale of a boy who likes to discover new things, which leads to an unexpected encounter with a thief.

It adds that the story highlights determination, creativity and sibling bonds, and teaches the value of trial and error in discovery.

Who tells the story, and where is it set?

The narrator is Anita, fourteen years old, who tells the story in the first person. Her brother Anand, one year younger, thinks he is a scientist and keeps building "inventions" that never work out as planned.

The story is set in the family's house in a colony, in a row of houses with compounds, a drive and neighbours next door. The parents' trip is to Kharagpur, a few hours from Calcutta (now Kolkata).

Anand's room is next to the room Anita calls "our room"; Papa's room seems to be upstairs, since Anita is about to send Boppa there on the night of the break-in.

Sources: NCERT, Poorvi, Textbook of English for Grade 7, Unit 3 Dreams and Discoveries, "My Brother’s Great Invention", printed pages 91 to 108, with the listening transcript on page 136 (reprint 2026-27). The story is credited to Anita Rau Badami, from Battling Boats, Katha.

What do the before-reading activities ask?

Which inventions do the two riddles describe?

In pairs, the student guesses two inventions from short riddles written in the first person. The first is a concept invented by ancient Indian mathematicians: it adds value to numbers, and without it calculations in today's digital world would be impossible.

The second is an ancient Indian practice, now popular around the world, that focuses on physical and mental well-being. The answers are not printed; one possible answer is 1 zero and 2 yoga.

What would the world be like without inventions?

In groups of four, students discuss what the world today might have been like without inventions and discoveries. The answer is the student's own. One possible starting point: there would be no bulbs, wires, mixers, ovens, trains or films, and every one of these appears in Anita's account of her family.

How is the letter grid completed?

The grid hides five words for qualities of an inventor. Each row gives some letters, and the student fills the empty boxes.

All five qualities show up in Anand, from his tinkering to his fortnight of work on the time machine.

What happens in the story, part by part?

The story is printed in two parts. Part I opens in the middle of the action and then goes back to explain it. Part II covers the one night the parents are away.

Part I: who put that water bag there?

The story opens with Papa roaring from the front doorstep about a water bag, while Anita hisses to Anand that it is his burglar alarm. Ma finds Papa sopping wet and scowling, and Papa is sure "that boy" rigged it up. Anand vanishes until after dinner, when Papa has cooled down.

Part I: why did Anand build a burglar alarm?

Anita now introduces herself and her brother, who loves tinkering with gadgets, tools, dynamos and planks of wood. After a rush of thefts in the colony, Anand decides a burglar alarm is needed, and starts as soon as Papa leaves for the office and Ma for the market. Anita has to help, though she would rather finish her novel.

How was the alarm meant to work?

Anand shows her a blueprint, an elaborate drawing of doors, wires and bells; the word makes him feel professional. His plan runs in four steps.

1. A burglar opens the door.
2. The alarm is tripped off and makes a clanging sound.
3. A water bag is loosened and falls on the thief's head.
4. By then, the family calls the police.

Anita asks how the alarm will know it is a burglar. Anand explains smugly that a thief opens a door stealthily, so the alarm works only when the door is opened gently. Anita is sceptical but keeps quiet, and makes clear she is not involved if Papa asks.

Part I: what happened at the first trial?

Anita's doubts prove justified: Papa always opens the door softly, so the alarm caught him instead of a thief. For a week afterwards, Anand did not dare try out anything new.

At an open wooden front door, a man with a moustache, in a white shirt, blue tie and blue trousers, stands on a doormat holding a brown briefcase. Above the door frame, a small device with a wheel and a coiled wire tips over a red water bag, and water splashes onto his head as he grimaces.

Reference: NCERT Class 7 Poorvi, printed page 92

Part I: how did the time machine come about?

Then Anita and Anand see the film 'Back to the Future', which is all about a time machine, and Anand decides he must build a time machine too. Papa locks up his tool box and hides the key, and Ma keeps a wary eye on her oven and mixer, because on his "inventing binges" Anand takes apart gadgets for parts.

Amid hammering, sawing and clattering, Anand's room becomes a network of wires, springs, levers and bulbs, with an enormous panel meant to be the control switchboard. After a fortnight of frantic activity, he announces at lunch that the machine can be tried that night.

Part I: what did the parents decide?

Papa firmly refuses, though Ma, seeing Anand's crestfallen look, persuades him to at least look at the machine. As it turns out, it is not tried that day at all, and the next day the parents are going to Kharagpur for a wedding.

The children reassure a worried Ma that they can manage for one night, with Sharma Aunty next door. Ma makes Anand promise not to touch the time machine until they return. He agrees half-heartedly, hurt that his creation is not respected, and Anita is relieved.

Part II: who came in the night?

The parents leave by the afternoon train. Anand falls asleep, but Anita stays up reading a murder story. At about eleven thirty she hears a scratching at the front door, then a rattle and a click, and shakes Anand awake.

Before they can holler for help, the door swings open on a ruffianly man with a green scarf. Anita recognises Boppa, who had recently begun sweeping the compounds in their row of houses, and so knew exactly when the occupants were out. He threatens them with his cudgel, backs out and slides the latch in, locking them in.

Part II: which room did Boppa enter?

Boppa soon returns and demands to know where their father's room is. Anita is about to direct him upstairs when Anand quickly says it is the room next door. Once Boppa leaves, Anita angrily calls Anand a silly goose, because that is Anand's own room. Anand replies that it buys them time, since Boppa will take a while to find the light switch.

Anita, in green pyjamas, and Anand, in red striped pyjamas, stand close together beside a blue sofa, looking frightened. A man in a yellow checked shirt, dark trousers and a green checked scarf leans in through an open door, holding a wooden club. A night sky shows through a window with blue curtains.

Reference: NCERT Class 7 Poorvi, printed page 96

Part II: what were the strange noises?

Suddenly there is a crash and a loud scream, then muffled thumps, an eerie whine and a low hum from the next room. Anand gasps that Boppa has started his time machine. After a fainter howl and much clattering, the children shout as loudly as they can, and Mrs Sharma, her husband and Dr Mohan, another neighbour, come running and unlock the door.

Part II: where did Boppa go?

In Anand's room the machine is still humming softly, but no one is there except a green scarf near the panel of switches. Mr Sharma is sure Boppa did not run out, since the neighbours came in by the only way out, and a search upstairs finds nothing.

Mrs Sharma suggests Boppa ran out unseen, but Anand bursts out, eyes shining, that Boppa has gone through his time machine. Mr Sharma smiles fondly at the boy's imagination and stays the night to keep the children safe.

Part II: how does the story end?

Boppa is never seen again. Anand insists the machine worked and Boppa disappeared into the past. Papa has the machine dismantled because he thinks it is not safe, and Anita wonders whether he also had a niggling suspicion that it worked. Anand, now sure he is a genius, starts a new project: a telephone to contact creatures in outer space.

Who are the characters, and what is each like?

Anita, the narrator

Anita is a keen reader, still up with a book late on the night of the break-in. She is sceptical from the start, doubting the alarm's "guessing powers", and self-protective, making sure she is not blamed. Yet, as usual, she helps Anand, and it is she who wakes him and recognises Boppa, so she is braver than she admits.

Anand, the inventor

Anand is thirteen, smug about his blueprint and determined enough to spend a fortnight on the time machine. He grows untidy while inventing and is easily hurt when his work is not respected.

In danger he shows real presence of mind, sending Boppa into the wrong room to buy time. He stays imaginative to the end.

Ma and Papa

Papa roars, scowls and speaks grimly after the water bag, and says a firm NO to the time machine, yet agrees to look at it when Ma asks. Having the machine dismantled for safety shows he is protective, and perhaps half suspicious that it worked.

Ma is the peacemaker, soothing after the water bag and sorry for Anand's crestfallen look, yet watchful of her kitchen gadgets and stern when she makes Anand promise.

Who are the neighbours?

• Mrs Sharma (Sharma Aunty) is the neighbour the children can turn to; she suggests Boppa slipped out unseen.
• Mr Sharma (Sharma Uncle) asks what happened, is sure there is only one way out, smiles at the time machine idea, and kindly stays the night.
• Dr Mohan, also a neighbour, peers behind the door, asks whether the children imagined it all, and searches upstairs.

Boppa, the intruder

Boppa, the man who swept the compounds, is ruffianly, carries a cudgel, grins evilly and threatens the children, but he walks straight into Anand's trick. His disappearance is the story's great puzzle.

How is the textbook's character-trait table completed?

The task gives six traits for six spaces: creative, curious, careful, responsible, bothersome and confident. Bothersome is the worked example, so each of the other five is used once. The evidence column is paraphrased here.

Anand's words mention careful planning, but the alarm soaks Papa, so his line shows confidence rather than care. This is one sensible matching; a student who argues a different pairing should give the evidence for it.

What themes does the story explore?

Curiosity and the urge to invent

Anand cannot leave a gadget alone. A rush of thefts becomes a reason for an alarm, and a film becomes a reason for a time machine. The story treats this curiosity warmly: it causes trouble, but it also drives the plot.

Trial and error

None of Anand's inventions works as planned, yet he keeps going. He lies low for only a week after the alarm, and after the time machine is dismantled he starts on a space telephone. Trial and error appears as part of discovering, with failure as a step rather than an end.

Presence of mind in danger

Locked in by a real intruder, the children do not freeze. Anand sends Boppa into the wrong room, and their shouting brings help. Quick thinking, not strength, keeps them safe.

Family and sibling bonds

Anita grumbles but, as usual, helps Anand. The parents are strict but caring, and the neighbours come at once when called. The story's warmth comes from these bonds, which survive a soaking, a scolding and a scare.

Imagination and doubt

The ending sets imagination against ordinary explanation. The adults put the mystery down to an unseen escape or a boy's imagination, while Anand is sure the machine worked. The story never settles the question.

What is the message in one line?

Curiosity and invention may lead to mistakes and mess, but with persistence, quick thinking and a supportive family, they can also lead to surprising discoveries.

What are the tone, humour, language and style of the story?

How does the first-person narrator shape the story?

Anita tells the story as an older sister who has seen it all before, and her first-person voice is chatty and amused. She speaks straight to the reader, offering to "put you in the picture", wondering if the reader has seen the film, and promising to tell more next time.

Because she is part of the events, the reader knows only what she sees and hears.

Where does the humour come from?

• Irony: the alarm built to catch a thief catches Papa, and the time machine no one was allowed to try is started by the thief himself.
• Exaggeration: Anand looks like a savage while inventing, and has frightened people half to death.
• Comic repetition: Papa is "angry as angry could be", and Boppa will be "as mad as mad can be".
• Playful words: hoo-ha, holler and silly goose keep the tone light.

How is suspense built in Part II?

The tone shifts from comic to tense. Late at night, with a murder story in her hands, Anita hears sounds that grow more alarming. Locked in, the children must guess at what is happening next door from a crash, a scream, thumps, a whine and a hum. Short, startled lines of speech quicken the pace.

Which sound words and expressions stand out?

Sound words such as clanging and crash, idioms such as leaving the coast clear, and the binomial peace and quiet make the voice natural and lively.

A boy in a blue T-shirt sits at a desk under a pink lamp, smiling as he joins what looks like a battery by wires to a bulb on a wooden block, beside a small green circuit board. Lower down, a girl in a red top points to large letters reading Back to the Future, with a thought bubble showing a mixer and an oven.

Reference: NCERT Class 7 Poorvi, printed page 93

Why is the ending left open?

The story has an open ending. Anita's half-serious guess about Papa's suspicion keeps the joke going, and the space telephone hints that Anand's adventures will continue.

What are the key quotations?

The trouble with him is that he thinks he is a scientist.

Speaker: Anita. Context: introducing Anand; it sets up the gap between how he sees himself and how his sister sees him.

Nothing will go wrong this time. I've planned it out carefully.

Speaker: Anand. Context: showing Anita his blueprint; the line is ironic, since the alarm soaks Papa.

When I say NO, I mean NO.

Speaker: Papa. Context: refusing to let Anand try the time machine; the capital letters show how firm he is.

The one next to this one.

Speaker: Anand. Context: his quick answer when Boppa asks for Papa's room; it shows his presence of mind.

My time machine! He's gone through that!

Speaker: Anand. Context: his explanation, with shining eyes, when Boppa cannot be found.

What an imagination this boy has!

Speaker: Mr Sharma. Context: his fond reply to Anand's claim; it gives the adults' view of the mystery.

What do the words in the margins mean?

Twenty-nine words and phrases are explained in the margins beside the story. The meanings below are as printed.

What are the answers to the "Let us discuss" tasks?

How is the cause-and-effect table completed?

The first task, after Part I, asks for the missing cause or effect in four rows. The book's own wording is paraphrased here.

Did Anand keep his promise about the time machine?

This question asks for an opinion with reasons. One possible answer: in a way, yes. Anand did not switch the machine on while his parents were away; Boppa started it after Anand sent him into that room.

A student could also argue no: Anand had promised only half-heartedly, and by naming his own room as Papa's he sent the intruder straight to the machine. Either answer is acceptable if it is backed by these details.

What is the correct order of events?

The second task, after Part II, lists five events out of order. In the order they happen, they are 4, 1, 5, 3 and 2.

1. (4) Anita wakes Anand and tells him someone is trying to get into the house.
2. (1) The door swings open, and they see Boppa, who gives an evil grin.
3. (5) Anand misleads Boppa into entering his own room instead of Papa's.
4. (3) Mrs Sharma, her husband and Dr Mohan arrive, the door is unlocked, and they come in to help.
5. (2) Boppa is nowhere to be found, but his green scarf lies near the time machine.

In the story, the scarf lies near the panel of switches, which is part of the time machine.

How are the "Let us think and reflect" questions answered?

Extract 1: Anita introduces Anand

1. (i) introduce. Anita wants to introduce the situation, giving the background before she tells what happened.
2. (ii) A, dismantling and creating. The margin glosses tinkering as experimenting or fiddling; Anand takes gadgets apart for parts and keeps creating inventions.
3. (iii) B, creative and experimental. He builds inventions of his own and tries them out, even though they never work as planned.
4. (iv) Anita thinks the trouble with Anand is that he only thinks he is a scientist, since his inventions never work out as they are supposed to. Anand, on the other hand, sees himself as a real scientist.

Extract 2: the wrong room

1. (i) Anita was angry with Anand because he sent the intruder into his own room instead of letting her direct him upstairs, and she feared Boppa would come back furious when he found out.
2. (ii) Anand quickly named his own room as Papa's, reasoning that Boppa would take a while to find the light switch, which gave the children time to think and shout for help.
3. (iii) B, Anand's time machine getting activated. Anand gasps that Boppa has started his machine, and it is still humming when the neighbours arrive.
4. (iv) (c) C and E. The atmosphere is tense and suspenseful: the children are locked in and hear a crash, a scream and strange sounds from a room they cannot see into.

Task II of this exercise is the character-trait table, completed in the section on the characters.

What are the answers to the six questions?

1. What prompted the burglar alarm? There had recently been a rush of thefts in the colony, and Anand decided that what was needed was a burglar alarm.

2. How did Papa become its target? Anand rigged the alarm to work only when the door was opened gently, thinking only a thief would do that. Papa always opens the door softly, so the alarm went off for him and the water bag soaked him.

3. How did the family react to his ideas? Papa reacted with anger and a firm NO, and locked up his tool box. Ma was soothing and sympathetic but guarded her oven and mixer. Anita doubted his ideas and kept clear of blame, though she still helped.

4. How did Anand behave on his inventing binges? He took apart the gadgets in the house for parts, made a din of hammering and sawing, looked like a savage, skipped combing his hair and let no one into his room.

5. Why did Mr Sharma not believe Anand? To him, a homemade time machine sending a man away was simply the boy's imagination, so he smiled fondly at the idea and sent the children to bed.

6. An ending for Boppa. The answer is the student's own. One possible ending: Boppa slipped out unseen in the dark and fled the colony, too frightened by the whirring machine ever to return, so the scarf was the only trace he left.

What words and expressions does the chapter teach?

What is onomatopoeia?

Onomatopoeia is the use of words that imitate the actual sounds of the things they describe, such as the boom of a firework, the ding-dong of a bell, the pitter-patter of raindrops and the tick-tock of a clock. The highlighted example from the story is clanging.

In the story the low hum comes in a frightening moment, so there it adds to the strangeness rather than soothing anyone.

What are binomials?

Binomials are expressions of two words, usually linked by a conjunction such as and or or, that are used together in a fixed order. Between them, the two words convey either a single meaning or an opposite. The story's example is peace and quiet.

Which phrasal verbs fill the paragraph?

The paragraph about a rainy function uses all five phrasal verbs from the box, three of which appear in the story: rigged up, tripped off and turned out.

1. (i) ran out of time to set up
2. (ii) quickly rigged up some decorations
3. (iii) accidentally tripped off the fire alarm
4. (iv) the rain let up as the guests arrived
5. (v) the function turned out to be a huge success

Which idioms complete the sentences?

An idiom is a phrase whose meaning is different from the literal meaning of its words, like a special saying that people understand in a specific way. For example, raining cats and dogs means raining very heavily. The story's examples are got on Papa's nerves and frightened someone half to death.

1. Shekhar knew he would get a shelling for breaking the vase.
2. We fell over ourselves trying to help the injured dog.
3. Faizy distracted Kanchan, leaving the coast clear for the surprise.
4. Constant power fluctuations can get on our nerves.
5. An unexpected noise at night can frighten me half to death.

How are the simple past and the past perfect used?

What is the rule?

The grammar task highlights three words in Anita's sentence about Boppa: was, had and begun, as in "who had recently begun sweeping out the compounds". The sentence refers to two completed actions.

• Recent past (new action): the simple past, here was, for the moment Anita recognises him.
• Later past (old action): the past perfect, here had begun, for what Boppa had started doing some time before that night.

In time order, the old action is the one completed first. The past perfect is formed with had and the past participle, as in had begun, had vanished and had packed.

Which verbs are underlined?

1. (i) Past perfect: had rushed. Simple past: was and found.
2. (ii) Past perfect: had vanished and had cooled. Simple past: reappeared.

In sentence (i), the exercise prints had rushed, but the same sentence in the story uses the simple past, rushed. Words such as to see, standing and scowling are not underlined, since they are not simple past or past perfect forms.

How are the blanks filled?

(i) A. had finished, B. decided, C. left, D. realised, E. had forgotten. Rohan finished his homework before he decided to walk, and forgot his keys before he realised it, so those two take the past perfect.

(ii) A. reached, B. had already left, C. waited. The train left before the speakers reached the station, so it takes the past perfect.

How are the sentences combined?

The time expressions are before, after, by the time and when. The worked example puts the old action in the past perfect: Rohan had packed his suitcase before he left for the airport.

1. (ii) We had started work before he arrived in the morning.
2. (iii) They had set up the tents by the time the others brought food and medicine.
3. (iv) The students had become quiet when they heard the teacher coming.
4. (v) The villagers had left the village before the flood submerged the entire area.

In (iv) the table lists becoming quiet as the old action. If the student takes the hearing to come first, the past perfect moves to it: after the students had heard the teacher coming, they became quiet.

What do the listening, speaking, writing and exploring tasks ask?

Listening: what do Anita and Toby talk about?

The student listens to a conversation between Anita and Toby, a Martian stranded on Earth who has become her friend. It echoes the end of the story, where Anand plans a telephone to contact creatures in outer space.

The true statements are 2 and 3. Anita says she is happy to have Toby as her friend, and she asks how he sees with only one eye, a facial feature.

• Statement 1 is false: Toby misses his people and home, not his school.
• Statement 4 is false: Toby says Anita had an apple for breakfast, not a banana.
• Statement 5 is false: Toby says he can see even with his eye closed, not that he sees much clearer.

In item 5, the exercise prints woods, while the transcript has the singular wood.

Speaking: how are words ending in -ough said?

The task notes that though rhymes with low and enough rhymes with puff, so words ending in -ough are pronounced in very different ways. The six words in the box are sorted into five sound groups.

Enough, rough and tough rhyme with puff, a sound that has no box in the table. The read-aloud passage about a woman working on her farm uses ten -ough words in bold, and the tongue twister packs tough, dough, bough, trough and cough into one sentence.

Writing: how is the vocation paragraph planned?

The student chooses a vocation, such as electrician, mechanic, chef, nurse or graphic designer, and writes a paragraph. The hints cover why the student likes it, the training and tools needed, co-workers and teamwork, dealing with customers, and pursuing it with pride. One possible answer:

I would like to become an electrician because, like Anand, I enjoy working with wires, switches and bulbs. I would need proper training and practice under an experienced electrician, and tools such as screwdrivers, pliers, a tester and safety gloves.

My co-workers would be other electricians and helpers, and teamwork matters because one careless mistake can endanger everyone. I would treat customers politely and explain each problem honestly, and I would work with pride, because safe wiring keeps homes lit and families safe.

Exploring: what do creativity, innovation and invention mean?

Creativity is thinking new things, innovation is doing new things, and an invention brings ideas or objects together in a novel way, creating something that did not exist before. All it takes is a simple idea. Human curiosity and creativity have led to many scientific and technological inventions.

The student may look for more Indian inventors and their inventions; any further names are the student's own research.

Glossary

• First-person narrator: the character who tells a story using I and we; here Anita, aged fourteen, tells events she took part in
• Blueprint: a detailed plan drawing; Anand's showed doors, wires and bells, and the word made him feel professional
• Presence of mind: the ability to think quickly and act sensibly in a sudden danger, as Anand did when he sent Boppa to the wrong room
• Irony: a result opposite to what was intended or expected, as when Anand's alarm for thieves soaks Papa instead
• Open ending: an ending that leaves a question unanswered; the story never confirms whether Boppa ran away or vanished into the past
• Onomatopoeia: the use of words that imitate the actual sounds of the things they describe, such as boom, ding-dong and tick-tock
• Binomial: two words, usually linked by and or or, used together in a fixed order, such as peace and quiet
• Phrasal verb: a verb joined with a small word such as up, off or out to make one meaning, such as rigged up and let up
• Idiom: a phrase whose meaning differs from the literal meaning of its words, such as raining cats and dogs for very heavy rain
• Simple past: the tense of a completed past action; of two past actions, it marks the newer one, such as was or found
• Past perfect: had with the past participle, used for the older of two completed past actions, such as had begun or had packed
• Invention: bringing ideas or objects together in a novel way, so that something new is created which did not exist before
• Innovation: doing new things, as distinct from creativity, which the chapter describes as thinking new things

Common errors and misconceptions

• Misconception: the burglar alarm caught a burglar. Correct: it soaked Papa, who always opens the door softly.
• Misconception: Anita is the younger child. Correct: Anita is fourteen, and Anand is one year younger.
• Misconception: Anand switched on the time machine while his parents were away. Correct: Boppa started it after Anand sent him into that room; the children were locked in next door.
• Misconception: Boppa was a stranger. Correct: he had recently begun sweeping the compounds in their row of houses, which is how he knew when the occupants were out.
• Misconception: the story proves that the time machine worked. Correct: it leaves the question open; Anand believes it worked, while the adults think Boppa ran out or that Anand is imagining things.
• Misconception: Papa dismantled the machine because it did not work. Correct: he thought it was not safe, and Anita wonders whether he suspected that it worked.
• Misconception: in a pair of past actions, the past perfect marks the newer one. Correct: the past perfect marks the old action, completed first; the newer action takes the simple past.
• Misconception: in the listening task, Toby says he sees much clearer with his eye closed. Correct: he says only that he can see even with his eye closed.

Exam-style questions with model answers

Q1. In the story, Anand rigs his burglar alarm to work only when the door is opened gently, because he believes a thief opens a door stealthily. When it works, a bell clangs and a water bag falls on the person's head. Papa always opens the door softly. Explain why the alarm soaked Papa instead of a burglar. [2 marks]

1. The alarm could not tell who was at the door: it went off for anyone who opened the door gently, which Anand wrongly assumed only a thief would do.
2. Papa always opens the door softly, so when he came home he set it off and the water bag fell on him, leaving him sopping wet.

Q2. The past perfect, formed with had and the past participle, is used for the old action, the one completed first; the simple past is used for the new action. Combine this pair using before: "Anand built a time machine." "His parents left for Kharagpur." Then name the tense of each verb in the new sentence. [2 marks]

1. Anand had built a time machine before his parents left for Kharagpur.
2. Had built is in the past perfect because it is the old action, completed first; left is in the simple past because it is the new action.

Q3. On the night of the break-in, Boppa locks Anita and Anand in their room, then returns and asks where their father's room is. Anita is about to direct him upstairs, but Anand quickly says it is the room next door, which is his own room with the time machine. He says Boppa will take a while to find the light switch, and suggests they shout. Their shouting brings the neighbours. Explain three ways in which this shows Anand's presence of mind. [3 marks]

1. He thinks fast under threat, answering before Anita can direct the intruder upstairs.
2. He sends Boppa to his own room instead of Papa's, reasoning that Boppa will take a while to find the light switch there, which buys the children time to think.
3. He uses that time sensibly by suggesting they shout, and their shouting brings the neighbours to the rescue.

Q4. In the story, an alarm meant for thieves soaks Papa, who always opens the door softly. Anita says Papa was "angry as angry could be". While inventing, Anand looks like a savage and stops combing his hair. Because Anand takes apart gadgets for parts, Papa hides the key to his tool box, and Ma watches her oven and mixer. The time machine Anand was forbidden to use is started by a thief. At the end, Papa has the machine dismantled, and Anita wonders whether he suspected it worked. Explain five sources of humour in the story. [5 marks]

1. Irony in the alarm: a device built to catch a thief catches Papa instead, because he is the one who opens the door gently.
2. Comic repetition in Anita's voice, as in "angry as angry could be", which makes Papa's fury funny rather than frightening.
3. Exaggeration about Anand, who looks like a savage and forgets to comb his hair while inventing.
4. The family's precautions, with Papa hiding his key and Ma guarding her kitchen gadgets, which show how much damage Anand's inventing does.
5. The twist that the forbidden time machine is started by the thief himself, followed by Anita's teasing hint that even Papa may half believe it worked.

Q5. In Part II, while the parents are away, Anita, up late with a book, hears a scratching, then a rattle and a click at the front door, and wakes Anand. Boppa, who sweeps the compounds, appears with a cudgel, threatens them and locks them in, then asks for their father's room, and Anand names his own room next door, where the time machine is. After a crash, a scream and strange machine noises, the children shout. The neighbours unlock the door but find only the green scarf near the humming machine, and Boppa is never seen again. Trace the events of the night in five steps. [5 marks]

1. Anita, reading late, hears a scratching at the front door and then a rattle and a click, and wakes Anand.
2. Boppa appears at the door with a cudgel, threatens them, and locks them in their room.
3. When Boppa returns to ask for their father's room, Anand sends him to the room next door, his own room with the time machine.
4. A crash, a scream and strange noises come from that room, and the children shout until the neighbours arrive and unlock the door.
5. Boppa has vanished: only his green scarf lies near the still-humming machine, and he is never seen again.

Q6. In the story, Anand loves tinkering and keeps creating inventions that never work out as they are supposed to. His burglar alarm, rigged to work only when the door is opened gently, soaks Papa, and for a week he dares not try anything new. After seeing a film, he spends a fortnight building a time machine, which Papa later has dismantled. Anand, convinced he is a genius, then begins a telephone to contact creatures in outer space. Explain in six points how the story shows the value of trial and error. [6 marks]

1. Anand's love of tinkering shows that inventing begins with curiosity and with experimenting on real gadgets.
2. His inventions, as Anita says, never work out as they are supposed to, so failure is presented as a normal part of trying new things.
3. The burglar alarm fails because of a flaw in its design: it cannot tell a thief from Papa, which the first trial exposes.
4. He is set back for only a week; a film soon sparks a bigger idea, the time machine, showing that one failure does not stop him.
5. His fortnight of work on the time machine shows the determination that trial and error needs, however often his inventions fail.
6. Even after the machine is dismantled, he starts a new project, a telephone to contact creatures in outer space, so the cycle of trying again continues.

Key takeaways

• "My Brother’s Great Invention" by Anita Rau Badami is the first piece in Unit 3, Dreams and Discoveries, of Poorvi, the English textbook for Grade 7.
• Anita, fourteen, narrates in the first person about her brother Anand, a year younger, who thinks he is a scientist.
• Anand's burglar alarm works only when the door is opened gently, so it soaks Papa, who always opens the door softly.
• Inspired by the film Back to the Future, Anand spends a fortnight building a time machine, but Papa forbids him to try it.
• While the parents are away, Boppa, who sweeps the compounds, breaks in, and Anand sends him into the room with the time machine.
• Boppa vanishes, leaving only his green scarf; Anand believes he went into the past, while Mrs Sharma suggests he ran out unseen.
• The story's themes are curiosity, trial and error, presence of mind, family bonds, and imagination set against doubt.
• The language work covers onomatopoeia, binomials, phrasal verbs, idioms, and the simple past and past perfect for two completed past actions.

Test yourself

How old are Anita and Anand?

Anita is fourteen years old, and her brother Anand is one year younger than her.

What made Anand decide that a burglar alarm was needed?

There had recently been a rush of thefts in the colony, so Anand got it into his head that a burglar alarm was needed.

Which film gave Anand the idea of building a time machine?

The film 'Back to the Future', which is all about a time machine.

Where did the parents go, and for how long?

They went to Kharagpur, a few hours from Calcutta (now Kolkata), for a wedding, leaving by the afternoon train and due back the following evening.

Who was Boppa?

He was the man who had recently begun sweeping the compounds in their row of houses, and he turned out to be the thief.

What did the neighbours find in Anand's room?

The time machine was still humming softly, and Boppa's green scarf lay on the floor near the panel of switches.

What is Anand's new project at the end of the story?

He has started work on a telephone to contact creatures in outer space.

Which binomial from the story means calm and freedom from noise?

Peace and quiet, as in the end of peace and quiet in the house once Anand began building his time machine.