in
in — noun
1. the written short form of 'inch', a measurement of length in the imperial system
the written short form of 'inch', a measurement of length in the imperial system. One inch is about 2.54 centimetres, and 12 inches make one foot.
The shelf needs a gap of at least 3 in. between each plank.
collocation: number + in. + between [objects]
Christopher bought a 2½ in. paintbrush for the fence.
collocation: [size] in. + noun (tool)
Quan's new tablet has a 10.5 in. screen that is bright and clear.
The recipe says to roll the dough to a thickness of ¼ in.
Cole checked the rain gauge in the yard and found 1.8 in. of water.
- inch
the full word, used in speech; 'in.' is only used in writing
- cm (centimetre)
metric equivalent; different measurement system
文法句型
number + in. + noun (measurement)
in — adjective
1. currently popular and considered fashionable by many people — used especially fo
currently popular and considered fashionable by many people — used especially for styles, activities, or ideas that are widely liked for a period of time
Eli said that short haircuts are in this season among college students.
be + in for describing fashion trends
The café on Green Street became in almost overnight after food bloggers praised it.
become + in for sudden popularity
Tanvi asked whether wearing bright colours is still in for office parties.
For a few months last year, roller skating was really in at the local park.
Lucas thinks that collecting vinyl records is in again among teenagers.
- trendy
informal like 'in', but can be used before nouns (e.g., a trendy jacket)
- fashionable
more formal than 'in'; commonly used in writing
- cool
broader meaning; can describe things beyond fashion
- popular
general term; not limited to fashion or trends
- out
direct opposite — means no longer fashionable
- unfashionable
more formal than 'out'
文法句型
be + in
become + in
seem + in
用法筆記
This adjective is always used after a linking verb (be, become, or seem) and never before a noun. For example, you cannot say 'an in style' — you must say 'a style that is in'.
常見錯誤
2. a written abbreviation meaning 'intranasal' — used in medical contexts to descri
a written abbreviation meaning 'intranasal' — used in medical contexts to describe medicine or treatment given through the nose
The doctor prescribed an in steroid spray for the patient's sinus infection.
medical abbreviation for intranasal route
According to the medical chart, the patient received a daily in treatment for her allergies.
Lucía checked the prescription and confirmed that the in medication was correctly listed.
The hospital guidelines recommend the in route for this type of flu prevention.
- intranasal
the full written form; more formal and clearer
文法句型
in + noun (medical product or route)
用法筆記
This is a written abbreviation used mainly in medical charts, prescriptions, and journal articles. In everyday speech, the full word 'intranasal' is used instead.
常見錯誤
in — adverb
1. moving from an outdoor or outer area into an enclosed space such as a building,
moving from an outdoor or outer area into an enclosed space such as a building, room, or container.
Christopher rushed in through the back door to escape the sudden rain.
motion verb: rush in
When the lunch bell rang, the students poured in from every direction.
phrasal pattern: pour in (large number)
Emma opened the garden gate and let the dog in before the storm started.
The old wooden window swung open, and cold air swept in from the street.
The window had been left open, and dry leaves had blown in overnight.
- inside
more explicit about final location, but less natural with motion verbs
- out
opposite direction — away from the enclosed space
文法句型
come in
go in
rush in
let + object + in
用法筆記
Commonly paired with verbs of motion (come, go, run, rush, pour) or caused-motion verbs (let, bring, take). The opposite sense uses the adverb 'out'.
常見錯誤
2. staying in a hospital, prison, or similar institution, usually to receive medica
staying in a hospital, prison, or similar institution, usually to receive medical care or as a legal requirement.
After breaking his leg, Tariro was in for five days of hospital treatment.
pattern: be in for [duration + reason]
The suspect was brought in for questioning about the bank robbery.
phrasal verb: bring [sb] in for
Kemi's grandmother is in for a routine check-up on her blood pressure.
After minor surgery, Dario was in for only one night before going home.
- out
discharged from hospital or released from custody
文法句型
be in for [treatment/reason]
bring [sb] in
用法筆記
Subject is a person staying in an institution. The phrase 'in for' specifies the reason. Frequently used in hospital and legal contexts. Distinguish from adverb sense 1 (FROM OUTSIDE), which involves movement rather than residence.
常見錯誤
3. present at one's home, workplace, or usual location, as opposed to being away or
present at one's home, workplace, or usual location, as opposed to being away or out.
I called Cyrus three times this morning, but he was not in.
common question/statement: [person] is/is not in
Is Mr. Chen in today, or is he attending the conference in Taipei?
The manager asked everyone to stay in until the safety drill was over.
Rachid left a note on the door saying he would be in by three o'clock.
The repair technician should be in sometime between two and four this afternoon.
- present
more formal; used in official or workplace contexts
文法句型
be in
stay in
ask if [sb] is in
用法筆記
Common in questions and negatives to ask or state whether someone is at their usual place. Often used with 'be', 'stay', or 'keep'.
常見錯誤
4. positioned inside something such as a box, room, or material rather than on the
positioned inside something such as a box, room, or material rather than on the outside.
The children were already in when the thunderstorm hit the village.
stative: [person] is/are in (already inside)
Élise opened the jewellery box and found a gold necklace still in.
stative with object: find [sth] in
The cat stayed in all day because of the freezing temperatures outside.
Reema closed the suitcase with her camera safely in.
Kasia kept the milk in so it would stay cold until breakfast.
文法句型
stay in
keep [sth] in
be in
用法筆記
Stative — describes something that already occupies an interior space, not the act of entering (see sense 1 FROM OUTSIDE). Object in 'keep [sth] in' must be something that can be stored or contained.
常見錯誤
5. having reached the scheduled stopping point, such as a station or airport, where
having reached the scheduled stopping point, such as a station or airport, where people may board or leave.
The train from Kaohsiung is in, arriving on platform two.
common announcement: [vehicle] is in
Vinícius checked the departures board and saw that his flight was already in.
Once the bus is in, passengers may board through the front door.
The ferry from Penghu should be in by six o'clock if the weather stays calm.
- arrived
broader meaning; can apply to people and packages too
- out
not arrived, or having departed
文法句型
[train/bus/plane/ferry] is in
come in
get in
用法筆記
Subject is always a vehicle (train, bus, plane, ferry, ship). Commonly heard in station and airport announcements. This sense is distinct from sense 1 (FROM OUTSIDE), which describes a person or thing entering a space.
常見錯誤
6. delivered or submitted to an official, an organisation, or an authority for revi
delivered or submitted to an official, an organisation, or an authority for review, consideration, or approval.
The scholarship application was in a week before the deadline.
passive: [document] is in
Dario made sure his tax return was in by the end of March.
Has the quarterly report been in yet, or is the finance team still finalising it?
If your entry is in before Friday, you are guaranteed a spot in the competition.
Cyrus checked twice to confirm that his signed form was in before the office closed.
文法句型
[document] is in
[form/application] has been in
用法筆記
Subject is always a document, form, application, report, or similar written item. Rarely used for spoken submissions. Common in academic, administrative, and competition contexts.
常見錯誤
7. toward the shore, beach, or harbour area — used especially to describe the movem
toward the shore, beach, or harbour area — used especially to describe the movement of the tide or a ship arriving at land.
The tide was coming in fast, covering the sandy stretch of beach.
come in — describing tide moving toward shore
Stephanie watched the ferry come in as the sun began to set over the water.
After a long night at sea, the fishing boat headed in to the harbour.
The coastguard radioed that the rescue vessel was coming in to pick up the sailors.
Roya watched the sailboat come in through the narrow channel between the rocks.
- ashore
more formal and suggests reaching the shore specifically, rather than moving toward it
- toward land
less idiomatic; describes direction without the sense of arrival built into 'in'
- out
used of the tide moving away from shore (e.g. the tide is going out)
用法筆記
The most common verbs used with this sense are come in and head in, describing the movement of tides, boats, or ships toward land.
常見錯誤
8. used after a verb to show that an action makes something finished, submitted, or
used after a verb to show that an action makes something finished, submitted, or fully incorporated — for example, handing in homework or filling in a hole.
Maeve handed her essay in just before the midday deadline.
hand in — submitting work for completion
The builders filled the hole in with fresh concrete yesterday morning.
fill in — making a surface complete again
Joon gave his report in to the department manager on Tuesday.
The teacher asked the class to fill the missing answers in on the worksheet.
Noa dropped the signed contract in at the office on her way home.
用法筆記
Only used as a particle attached to verbs like hand, fill, give, drop, and send. It cannot stand alone as the adverb for this meaning — the verb must precede it in a phrasal construction.
常見錯誤
9. within the legal playing area of a sport such as tennis or badminton, so that pl
within the legal playing area of a sport such as tennis or badminton, so that play continues because the ball or shuttlecock has not landed outside the marked lines.
The umpire signalled that the ball was in, so the point continued.
be in — within playing boundaries
Manuela watched the line judge call the serve in during the final set.
Dario argued that the shuttlecock had clearly landed in for the winning point.
A point is awarded when the opponent's shot lands in and cannot be returned.
The tennis coach showed beginners how to check if a ball is in or out.
- within the lines
descriptive phrase rather than a single synonym; used in tennis and badminton
- good
shorter term used in some sports to mean the ball stayed in bounds
- out
the ball or shuttlecock has landed outside the playing area
用法筆記
Almost always used with the verb be or land, and frequently contrasted with out in sports commentary. The subject is always a ball, shuttlecock, or similar game object.
常見錯誤
10. having the right or opportunity to play next in a game or sport, especially one'
having the right or opportunity to play next in a game or sport, especially one's turn to bat, serve, or hit the ball.
"You are in next," the table tennis coach said to Chidi.
be in next — taking one's turn to play
Stefan checked the scoreboard to see which player was in to bat.
The referee called Ayesha's name and signalled that she was in for the next round.
After waiting two hours, Lucía was finally in for her turn on the court.
When a player gets injured, the substitute is in to take their place.
- out
the player has been removed from the game or has finished their turn
用法筆記
Subject is always a person (the player). Distinguish from the WITHIN BOUNDS sense (sense 9), where the subject is the ball. Frequently followed by next or an infinitive clause (in to bat, in to serve).
常見錯誤
in — prefix
1. a letter group placed at the start of an adjective, or a word made from an adjec
a letter group placed at the start of an adjective, or a word made from an adjective, to show the opposite meaning; for instance, adding 'in-' to 'visible' gives 'invisible', meaning not able to be seen.
The report was incomplete, so Yumi asked her teacher for more time.
in- + complete = incomplete (not complete)
Aoi corrected the incorrect figures in the spreadsheet before the meeting.
in- + correct = incorrect (wrong), used attributively before a noun
Since the workers went on strike in March, the factory has been inactive.
A chameleon can make itself almost invisible by changing its skin colour.
For the beach party, Christopher suggested informal clothes instead of suits.
- un-
the most common English negative prefix, used with many adjectives of Germanic origin (unhappy, unfair); 'in-' typically appears with words of Latin origin (inactive, incorrect).
文法句型
in- + adjective
in- + adjective-derived noun
用法筆記
Before the letter 'l', the prefix changes to 'il-' (illegal); before 'b', 'm', or 'p', it becomes 'im-' (impossible, imbalance); before 'r', it becomes 'ir-' (irregular). These adjustments make the combined word easier to pronounce.
常見錯誤
in — preposition
1. located inside the boundaries of a container, room, building, or outdoor area —
located inside the boundaries of a container, room, building, or outdoor area — for example, a key lying inside a drawer, a child standing inside a room, or a boat floating on the middle of a lake.
The cat is sleeping in the box beside the sofa.
in + [container]: physical location inside
Harper keeps her notebooks in that blue drawer.
There is fresh fruit in the bowl on the table.
The children are playing in the park near the school.
Aarav found his wallet in the pocket of his coat.
- outside
the opposite location — not inside the boundaries of something
文法句型
in + [container/place/area]
常見錯誤
2. showing movement or direction from outside to the inside of a place, container,
showing movement or direction from outside to the inside of a place, container, or area — used with verbs such as put, go, get, jump, throw, or walk.
Haruto jumped in the pool with a big splash.
[verb of motion] + in + [destination]: movement into
Élise put the clean clothes in the wardrobe.
put + in + [container]: inserting something
The dog ran in the house when the rain started.
Antonia threw the empty bottle in the recycling bin.
Mert dipped his brush in the paint before starting.
文法句型
[verb of motion] + in + [destination]
用法筆記
This sense overlaps with the preposition 'into'. In everyday speech, 'in' is commonly used instead of 'into' after verbs of movement ('get in the car', 'jump in the water'). 'Into' is preferred in more formal writing.
常見錯誤
3. forming part of a group, organisation, activity, or system — being one of the el
forming part of a group, organisation, activity, or system — being one of the elements that make up a whole, such as a member of a team, an ingredient in a recipe, or a component in a plan.
Dewi has a small role in the school play this year.
in + [activity]: being part of an event
There are twelve players in a volleyball team.
in + [group]: membership
Adisa invested money in his cousin's new restaurant.
The new system has some problems in its design.
Yael believes in the importance of helping others.
- part of
more direct; 'in' is the preposition while 'part of' is a phrase
文法句型
in + [group/organisation/activity]
4. at some point inside a named time segment or throughout the whole of it — used w
at some point inside a named time segment or throughout the whole of it — used with parts of the day, months, seasons, years, and longer historical spans.
We often go to the beach in the summer months.
in + [season]: within a season
The shop is very busy in the afternoon after lunch.
Hui likes to read stories in the evening before bed.
In the morning, the streets are quiet and empty.
Many birds fly south in the winter to find warmth.
- during
more explicit about the time span; 'in' is shorter and more conversational
文法句型
in + [time period]
用法筆記
Use 'in' with parts of the day (morning, afternoon, evening), months (in April), seasons (in summer), and years (in 2024). Use 'at' for clock times (at 3 o'clock) and 'on' for days and dates (on Monday, on July 5th).
常見錯誤
5. within the time that lies between two specific events, dates, or reference point
within the time that lies between two specific events, dates, or reference points — used to describe something that happens or exists in the interval.
In the time between school and dinner, Bao does his homework.
in + [interval between two events]
The house was rebuilt in the years just after the war.
We plan to finish the painting in the week before the party.
The weather changes a lot in the period between spring and summer.
Haruto grew eight centimetres in the year after he turned eleven.
- within
more formal; can also mean 'no longer than'
文法句型
in + [time span between two reference points]
用法筆記
Distinguish from the DURING sense (sense 4): sense 4 refers to a broad or recurring period (in summer, in the morning), while this sense names a span bounded by specific reference points (in the week before the exam, in the years after the war).
6. no more than a stated length of time — used to set an upper limit on how long a
no more than a stated length of time — used to set an upper limit on how long a process takes, emphasising the speed or capacity with which something can be done, such as cooking a meal in twenty minutes or reaching a shop in five minutes.
The pasta will be ready in about ten minutes.
in + [duration]: maximum time needed
Ravindra ran the race in under twelve seconds.
The doctor can see you in about half an hour.
The whole class finished the test in just twenty minutes.
Hui can walk to the station in five minutes from her house.
- within
more formal; emphasises the upper time limit
文法句型
in + [time duration]
用法筆記
This sense answers 'how long does it take?' and can be rephrased with 'within' ('within ten minutes') or 'in no more than' ('in no more than ten minutes'). Not to be confused with sense 4 (DURING), which answers 'when?' — compare 'I did it in the morning' (when) with 'I did it in one hour' (how long it took).
常見錯誤
7. before a specific time limit runs out — used to indicate that an event or result
before a specific time limit runs out — used to indicate that an event or result will happen by the time a stated period finishes, such as completing a project within a week or wrapping up a meeting inside an hour.
Eitan finished the exam in just forty-five minutes.
in + time period for completion
The bus will be here in ten minutes, so please get ready.
Jisoo learned to swim in three weeks, which surprised her family.
I will have the report ready for you in an hour.
Piotr promised to finish the website design in three weeks, before the deadline.
- within
more formal; emphasises that the action happens before the time limit, not at the end of it
- after
only when 'in' carries the 'before the end of' meaning; 'after' places the event following the time limit
用法筆記
Common in future-tense statements about how soon an action or event will happen. The time expression that follows can be a number + unit ("ten minutes," "three weeks") or a vague duration ("a while," "no time").
常見錯誤
8. in a particular state, situation, or emotional condition that affects you — for
in a particular state, situation, or emotional condition that affects you — for example, being in trouble with a landlord, in love with someone, or in a dangerous place.
Jisoo is in trouble with her landlord for not paying the rent.
in + noun phrase (state or situation)
The company is in a difficult financial situation this year.
Leo was in love with Amira from the moment they met.
After the earthquake, the whole town was in shock for days.
Vinícius found himself in a dangerous position on the mountain.
- in the middle of
more informal; emphasises being actively involved in a situation
- undergoing
more formal; used especially for processes like medical treatment or training
- out of
direct opposite: 'out of trouble' vs 'in trouble,' 'out of danger' vs 'in danger'
用法筆記
Frequently followed by a noun phrase that names a state, emotion, or situation: 'in trouble,' 'in love,' 'in shock,' 'in danger,' 'in a position.' The subject is usually a person, group, or organisation that is affected.
常見錯誤
9. using a particular language, style, material, or format to communicate something
using a particular language, style, material, or format to communicate something — for example, writing a message in English, painting a picture in oil, or stating a price in dollars.
Please write your answer in English, not in your native language.
in + language name
The secret message was written in a code that only the team could understand.
Karim painted the portrait in oil, which gave it a rich texture.
All prices are listed in US dollars on the website.
Amira explained her idea in simple words so everyone could follow.
用法筆記
Followed by a noun that specifies the medium of communication: a language ('in English,' 'in French'), a format ('in writing,' 'in code'), a material ('in oil,' 'in pencil'), or a manner ('in simple words').
常見錯誤
10. as a reaction, response, or emotional consequence of something that has just hap
as a reaction, response, or emotional consequence of something that has just happened — for example, calling your parents in celebration of getting a job, or leaving a party in anger after an argument.
In response to the criticism, the manager changed the team's schedule.
in + reaction noun phrase at clause start
The government raised taxes in an effort to reduce the national debt.
in + purpose noun phrase
Christopher called his parents in celebration of getting the job.
Andrei left the party in anger after the argument with his friend.
The Kim family donated money in memory of their grandmother who passed away.
- as a result of
more explicit about causation; works as a full phrase replacement for the whole 'in + noun' structure
- due to
formal; emphasises the reason rather than the action taken in response
用法筆記
The 'in + noun' phrase usually appears at the beginning of a clause or after the main verb. Common structures: 'in + noun' (in anger), 'in + noun + of + noun phrase' (in celebration of the win), 'in + noun + to-infinitive' (in an effort to help).
常見錯誤
11. showing how people or objects are positioned, grouped, or divided — for example,
showing how people or objects are positioned, grouped, or divided — for example, sitting in a circle, arranging chairs in rows, or cutting a cake in half.
The students sat in a circle so they could see each other's faces.
in + shape/arrangement (circle)
Please arrange the chairs in rows of five for the ceremony.
The family photos were hung in a line along the hallway wall.
Gita divided the cake in half and gave one piece to each child.
The team stood in a straight line waiting for their turn.
- arranged as
more explicit; used in descriptions: 'arranged as a circle'
- in the shape of
more literal; emphasises the physical form: 'in the shape of a half-moon'
用法筆記
Followed by a noun phrase that describes the shape, pattern, or division: 'in a circle,' 'in rows,' 'in half,' 'in a line.' The verb is often about placing, dividing, or positioning (arrange, sit, stand, hang, divide, cut).
常見錯誤
12. used when talking approximately about how old someone is or how hot or cold the
used when talking approximately about how old someone is or how hot or cold the weather is — for example, a person in their early thirties, or a temperature in the high twenties.
Niran is in his early thirties, but he looks much younger.
in his/her + plural age range
The temperature today is in the high twenties, perfect for the beach.
in the + temperature range
My grandmother is in her nineties and still walks every morning.
The temperature outside is in the low forties, so bring a coat.
Most students in the class are in their late teens.
- around
more general; can replace 'in' for both age and temperature but sounds less natural in fixed patterns like 'in his twenties'
- approximately
formal; used in writing or statistical contexts
用法筆記
For age, followed by a possessive determiner ('his,' 'her,' 'their,' 'its') plus a plural number or 'teens' — 'in his twenties,' 'in her early thirties,' 'in their late teens.' For temperature, followed by 'the' plus a plural number — 'in the low forties,' 'in the high twenties.' Modifiers like 'early,' 'mid,' and 'late' make the reference more specific.
常見錯誤
13. taking part in or having a connection with something such as an event, a field o
taking part in or having a connection with something such as an event, a field of study, or an area of work.
Hoa has been in the music industry for over twelve years now.
in + [field/profession] for participation
Eli and his team are in the final stage of building the new bridge.
Noor is not in the habit of checking work messages after ten at night.
The librarian was deeply involved in the community reading programme.
Are you still in the student exchange programme for next semester?
- involved in
more explicit about active participation; 'in' alone is shorter and more common in everyday speech
- engaged in
more formal; implies active, focused involvement rather than simple membership
- out of
the opposite of being involved in an activity or field
14. having clothes, jewellery, or other items on your body as part of your appearanc
having clothes, jewellery, or other items on your body as part of your appearance.
Élise looked elegant in her long silk dress at the wedding.
in + [clothing] for describing appearance
The woman in the red hat is waiting for the tour guide.
Arjun felt relaxed in his old cotton shirt and jeans.
Children in bright yellow rain boots jumped into every puddle.
Antonia walked onto the stage in a pair of simple black shoes.
- wearing
more active and specific; 'in' describes a state or visual impression
- dressed in
slightly more formal; 'dressed in a suit and tie'
用法筆記
Followed by a noun phrase describing the clothing or accessory. Common in descriptions of people: 'the man in the suit', 'the girl in glasses'.
常見錯誤
15. showing how a number or quantity relates to the total of which it is a part, oft
showing how a number or quantity relates to the total of which it is a part, often expressed as a rate, ratio, or proportion.
One in every five students at the school speaks two languages.
one in + [number] for expressing proportions
The success rate was about nine in ten for that medical treatment.
Tax of twenty dollars in every hundred is taken from your pay.
Only two people in the whole group of fifty had ever been abroad before.
A litre of paint covers roughly twelve square metres in every coat.
用法筆記
The structure is typically '[number] in [total]': 'three in ten', 'one in a million'. The total can be explicit ('in every hundred') or implied ('in ten').
16. used when describing a particular feature, quality, or aspect that someone or so
used when describing a particular feature, quality, or aspect that someone or something has, often in comparisons or judgements.
The two suitcases are similar in size but very different in weight.
similar/different in + [quality] for comparisons
Feng is quite tall for his age but still a child in behaviour.
The old house was cold in winter and dark in every room.
Hana is ahead of her classmates in mathematics but behind in reading.
These phones are nearly equal in price so pick the one you like best.
- regarding
more formal; 'regarding price' instead of 'in price'; less natural in everyday speech
- with respect to
very formal; used in academic or legal writing rather than conversation
用法筆記
Often paired with adjectives of comparison: 'similar in', 'different in', 'equal in', 'alike in'. The noun after 'in' names the specific quality being judged.
17. while carrying out an action that produces a particular result, change, or situa
while carrying out an action that produces a particular result, change, or situation at the same time.
In leaving the company early, Christopher missed out on a large bonus.
in + -ing for cause-and-effect
The chef burned his hand in taking a hot tray out of the oven.
In choosing the cheaper materials, the builder saved over two thousand dollars.
Nadia cut her finger in opening the tin of beans for dinner.
In helping his neighbour carry furniture upstairs, David hurt his back.
用法筆記
Always followed by an '-ing' verb form. The subject of the main clause is usually also the doer of the '-ing' action. This structure connects a physical action to its immediate consequence.
常見錯誤
18. used to introduce the specific reason why a given statement is true or valid, es
used to introduce the specific reason why a given statement is true or valid, especially in formal writing or explanations.
The surgery was a success in that the tumour was fully removed.
in that + clause for giving a reason
Ilan's advice was helpful in that it saved us a great deal of time.
The design is clever in that it uses very little energy to run.
Baraka was lucky in that his passport was found before the flight left.
Yara's plan was risky in that it depended entirely on good weather.
- because
less formal and far more common in everyday English; 'in that' is more precise and used in formal writing
- since
similar formality to 'in that'; works when the reason is already known or obvious
- for the reason that
equally formal but less common; 'in that' is more concise
用法筆記
Almost always occurs in the fixed expression 'in that' followed by a clause. More formal than plain 'because'. Common in academic writing and formal explanations. The clause after 'in that' specifies the exact respect in which the statement is true.
常見錯誤
in — suffix
1. Added after a verb, this suffix produces a noun for a joint gathering that numbe
Added after a verb, this suffix produces a noun for a joint gathering that numbers of people join, often to make a protest or back a shared belief.
Marco and his classmates held a sit-in at the library to protest fee increases.
suffix -in: verb 'sit' → noun 'sit-in' (protest)
Élise helped organise a teach-in about climate change at the local community centre.
suffix -in on 'teach' gives 'teach-in' (educational event)
Aoi joined a die-in on the main street to raise awareness about traffic safety.
Vivek and his neighbours planned a read-in at the park to share neighbourhood stories.
Beatriz joined a lie-in outside the factory gates to call for better working conditions.
文法句型
[verb] + in
用法筆記
The -in suffix attaches to certain verbs to form countable nouns (e.g., two sit-ins). It is most common in informal news reporting and activist language. Not every verb can take this suffix — learners should learn the established -in words as fixed vocabulary items.