You use when to ask questions about the time at which things happen.
When are you going home?
When did you get married?
When is the press conference?
When were you in this house last?
'I'll be there this afternoon.'—'When?'
2. conjunction
If something happens when something else is happening, the two things are happening at the same time.
You can even track how many calories you burn when sleeping.
Mustard is grown in the field when weeds are there.
3. conjunction
You use when to introduce a clause in which you mention something which happens at some point during an activity, event, or situation.
When I met the Gills, I had been gardening for nearly ten years.
4. conjunction
You use when to introduce a clause where you mention the circumstances under which the event in the main clause happened or will happen.
When he brought Imelda her drink she gave him a genuine, sweet smile of thanks.
I'll start to think about it when I have to write my report.
5. conjunction
You use when after certain words, especially verbs and adjectives, to introduce a clause where you mention the time at which something happens.
I asked him when he'd be back to pick me up.
I don't know when the decision was made.
It is important to check when the laboratory can do the tests.
6. pronoun
You use when to introduce a clause which specifies or refers to the time at which something happens.
He could remember a time when he had worked like that himself.
She remembered clearly that day when she'd gone exploring the rockpools.
In 1973, when he lived in Rome, his sixteen-year-old son was kidnapped.
7. conjunction
You use when to introduce the reason for an opinion, comment, or question.
How can I love myself when I look like this?
Emerald starlings are fairly small when compared with other such birds.
8. conjunction
You use when in order to introduce a fact or comment which makes the other part of the sentence rather surprising or unlikely.
Our mothers sat us down to read and paint, when all we really wanted to do was tomake a mess.
The temperature sensor is making the computer think the engine is cold when, in fact,it's hot.
English Easy Learning GrammarAdverbs and adverbialsWhen you want to add information about how, when, where, or to what extent somethinghas happened, you can use an adverbial. Many adverbials are members ... Read more
English Easy Learning GrammarSubordinationWhen two or more clauses are joined by a conjunction other than and, but, or, or yet,one of the clauses is the main clause; the other clauses are subordinate ... Read more
English Easy Learning GrammarThe interrogativeThe interrogative is normal for many questions. It contains a verb phrase that isfollowed by a subject. There are two main types of question: those that ... Read more
when in British English
(wɛn)
adverb
1.
a.
at what time? over what period?
when is he due?
b.
(used in indirect questions)
ask him when he's due
2. say when
3. (subordinating)
at a time at which; at the time at which; just as; after
I found it easily when I started to look seriously
4.
although
he drives when he might walk
5.
considering the fact that
how did you pass the exam when you'd not worked for it?
6.
at which (time); over which (period)
an age when men were men
noun
7. (usually plural)
a question as to the time of some occurrence
▶ USAGE When should not be used loosely as a substitute for in which after a noun which does not refer to a period of time: paralysis is a condition in which (not when) parts of the body cannot be moved
Word origin
Old English hwanne, hwænne; related to Old High German hwanne, hwenne, Latin cum
when in American English
(hwɛn; wɛn)
adverb
1.
a.
at what time?
when did they leave? he asked when he should go
b.
on what occasion or under what circumstances?
when do you double the final consonant?
c.
at what point?
when shall I stop pouring?
2.
at an earlier time and under different, often less favorable, circumstances
I knew him when
conjunction
3.
a.
at what time or point
they told us when to eat
b.
at the time that
when we were at college
4.
at which
a time when people must speak out
5.
as soon as
the runners started when the gun went off
6.
at whatever time; whenever
she smiles when you praise her
7.
although; while on the contrary
to complain when there's no reason to do so
8.
if; considering the fact that
how can he help when they won't let him?
pronoun
9.
what time
until when will you stay?
10.
which time
we came a week ago, since when we've been very busy
noun
11.
the time or moment (of an event)
the when and where of his arrest
Word origin
ME whenne < OE hwænne, akin to Ger wann, when, wenn, if, akin to hwa, who: see what
Examples of 'when' in a sentence
when
When she fretted about not doing well he would offer advice.
Times, Sunday Times (2016)
There are times when you really question what on earth you are doing.
Times, Sunday Times (2017)
They were used when distilleries used to malt their own barley.
Times, Sunday Times (2017)
Those flying solo will feel lucky in love when introduced to a chef.
The Sun (2016)
There was a time when we had none of this.
The Sun (2016)
When he talks about tomatoes you get the sense he means it as an allegory for life.
Times, Sunday Times (2016)
The question is when that vote should occur.
Times, Sunday Times (2016)
Drain after about 6 minutes when tender.
Times, Sunday Times (2016)
Labour went electric when we revised clause four and appealed to a much wider group and they want us to go back to playing folk again.
Times, Sunday Times (2016)
A perfect storm is about to hit investors tempted to use certain tax shelters, although there will be winners as well as losers when the clouds clear.
Times, Sunday Times (2016)
The only question is when it erupts and from where.
Times, Sunday Times (2016)
Only three overs had been bowled when spin was introduced for the first time.
Times, Sunday Times (2010)
Maybe this is that moment in time when you take gender equality a little more seriously.
Times, Sunday Times (2014)
The easiest times to do this are when the clouds are moving and there are gaps.
Freeman, Michael Collins Complete Guide to Photography (1993)
So what will they use then when they want to buy a loaf?
Times, Sunday Times (2014)
Luck is strong when you are introduced to your namesake.
The Sun (2009)
Forecasters can tell when clouds have snow in them.
Times, Sunday Times (2010)
The proposals also raise questions about when employers would be able to force workers to retire.
Times, Sunday Times (2009)
Any points deduction would lead to obvious questions about when and how it would be applied.
Times, Sunday Times (2009)
Yet companies must gamble that some of the compounds they discover or buy will work when they are introduced into humans.
Times, Sunday Times (2010)
It's a rare occurrence when contemporary dance performed by just two people sells out houses.
Times, Sunday Times (2008)
This makes the sketching much quicker, and this helps when the clouds are moving fast.
Crawshaw, Alwyn Crawshaw's Watercolour Studio (1993)
This is a problem and a natural occurrence when people are allowed to volunteer for leading others without first having the proper screening and training.
Christianity Today (2000)
When your question is a legal one, the green light on the computer will glow and you may proceed.
A Conceptual View of Human Resource Management: Strategic Objectives, Environments,Functions
But a useful question to ask when watching stuff like this is: just how much are the subjects enjoying being on camera?
Times, Sunday Times (2014)
A comma isn't necessary when the dependent clause comes at the end.
Bachmann, Susan (editor) & Barth, Melinda Between Worlds: A Reader, Rhetoric and Handbook (1995)
Set dashed underscore When the dependent clause comes first in the sentence, a comma is necessary.
Bachmann, Susan (editor) & Barth, Melinda Between Worlds: A Reader, Rhetoric and Handbook (1995)
Conversely, when the independent clause begins the sentence, there is no comma before the dependent clause that concludes the sentence.
Bachmann, Susan (editor) & Barth, Melinda Between Worlds: A Reader, Rhetoric and Handbook (1995)
In other languages
when
British English: when /wɛn/ ADVERB
You use when to ask what time something happened or will happen.
When are you leaving?
American English: when
Arabic: مَتَى
Brazilian Portuguese: quando
Chinese: 什么时候
Croatian: kada
Czech: kdy
Danish: hvornår
Dutch: wanneer
European Spanish: cuándo
Finnish: milloin
French: quand
German: wann
Greek: πότε
Italian: quando
Japanese: いつ
Korean: 언제
Norwegian: når
Polish: kiedy
European Portuguese: quando
Romanian: când
Russian: когда
Latin American Spanish: cuándo
Swedish: när
Thai: เมื่อใด เวลาใด
Turkish: ne zaman ki
Ukrainian: коли
Vietnamese: khi nào
British English: when /wɛn/ CONJUNCTION
You use when to talk about the time at which something happens.
I asked him when he'd be back.
American English: when
Arabic: عَنْدَما
Brazilian Portuguese: quando
Chinese: 在...的时候
Croatian: kada
Czech: když
Danish: når
Dutch: wanneer
European Spanish: cuando
Finnish: kun
French: quand
German: wenn
Greek: όταν
Italian: quando
Japanese: ･･･する時は
Korean: ...인 때
Norwegian: når
Polish: kiedy
European Portuguese: quando
Romanian: când
Russian: когда
Latin American Spanish: cuando
Swedish: då
Thai: เมื่อหรือขณะที่
Turkish: ne zaman
Ukrainian: коли
Vietnamese: khi
All related terms of 'when'
say when
to state when an action is to be stopped or begun , as when someone is pouring a drink
when in Rome
said to mean that people should follow the customs of the people they are visiting or living with
when pigs fly
If you say ' when pigs fly ' after someone has said that something might happen, you are emphasizing that you think it is very unlikely .
whene'er
at every or any time that; when
know when to stop
If you say that someone does not know when to stop , you mean that they do not control their own behaviour very well and so they often annoy or upset other people.
ready when you are
If you say to someone ' Ready when you are ', you are telling them that you are now ready to do something and that as soon as they are ready, you will do it.
when the dust settles
If you say that something will happen when the dust settles , you mean that a situation will be clearer after it has calmed down. If you let the dust settle before doing something, you let a situation calm down before you try to do anything else.
when it comes (down) to
You can use the expression when it comes to or when it comes down to in order to introduce a new topic or a new aspect of a topic that you are talking about.
when the chips are down
If you say that something happens when the chips are down , you mean it happens when a situation gets very difficult.
kick you when you are down
If you say that someone kicks you when you are down , you think they are behaving unfairly because they are attacking you when you are in a weak position .
when one's ship comes in
when one has become successful or wealthy
when push comes to shove
when a situation reaches a critical point and you must make a decision on how to progress
when someone's ship comes in
said to talk about what someone will do if they become rich and successful
when the balloon goes up
when the trouble or action begins
when the shit hits the fan
at the time that a crisis point is reached or disaster takes place
when your back is turned
when you are away or involved with something else
when it comes to the crunch
when a situation reaches a very important or difficult point and you must make a decision on how to progress
kick someone when they are down
to hurt , upset or criticize someone when they are already in a weak position or at a disadvantage
cross a bridge when one comes to it
to deal with a problem only when it arises ; not to anticipate difficulties
the dust settles when the dust settles
If you say that something will happen when the dust settles , you mean that a situation will be clearer after it has calmed down. If you let the dust settle before doing something, you let a situation calm down before you try to do anything else.
when you come/it comes down to it
You can use the expression when it comes down to it or when you come down to it for emphasis , when you are giving a general statement or conclusion .
if necessary/when necessary/where necessary
If you say that something will happen if necessary , when necessary , or where necessary , you mean that it will happen if it is necessary, when it is necessary, or where it is necessary.
they broke the mould when they made someone
said to mean that a particular person or thing is special or unique , and that there is nobody else or nothing else quite like them
when one person sneezes, another catches cold
said to mean that the things that happen to one country or person have a great effect or influence on other countries or people
when the cat's away, the mice will play
said to mean that people do what they want , or misbehave when their boss or another person in authority is away
come to think of it/when you think about it
You use expressions such as come to think of it , when you think about it , or thinking about it , when you mention something that you have suddenly remembered or realized .
someone will cross that bridge when they come to it
said to mean that someone intends to deal with a problem when, or if, it happens , rather than worrying about the possibility of it happening
when (or if, etc.) one's ship comes in (or home)
when (or if, etc.) one becomes rich
if it comes to the crunch/when it comes to the crunch
If you say that something will happen if or when it comes to the crunch , you mean that it will happen if or when the time comes when something has to be done.
Chinese translation of 'when'
when
(wɛn)
adv
(interrogative) 什么(麼)时(時)候 (shénme shíhou)
when did it happen?什么(麼)时(時)候发(發)生的？ (shénme shíhou fāshēng de?)
pron
(relative)
the day when当(當) ... 的那一天 (dāng ... de nà yī tiān)
conj
(in time clauses) 当(當) ... 时(時) (dāng ... shí)
when you've read it, tell me what you think当(當)你读(讀)过(過)之后(後)，告诉(訴)我你是怎么(麼)想的 (dāng nǐ dúguò zhīhòu, gàosù wǒ nǐ shì zěnme xiǎng de)
be careful when you cross the road过(過)马(馬)路时(時)要当(當)心 (guò mǎlù shí yào dāngxīn)
that was when we needed you那是我们(們)需要你的时(時)候 (nà shì wǒmen xūyào nǐ de shíhou)
she was reading when I came in当(當)我进(進)来(來)时(時)她正在阅(閱)读(讀) (dāng wǒ jìnlái shí tā zhèngzài yuèdú)
I know when it happened我知道什么(麼)时(時)候发(發)生的 (wǒ zhīdào shénme shíhou fāshēng de)
(= whereas) 而 (ér)
you said I was wrong when in fact I was right你说(說)我是错(錯)的而事实(實)上我是对(對)的 (nǐ shuō wǒ shì cuò de ér shìshí shang wǒ shì duì de)
(= considering) 既然 (jìrán)
why did you buy that when you can't afford it?既然你买(買)不起为(為)什么(麼)还(還)要买(買)？ (Jìrán nǐ mǎi bù qǐ wèi shénme hái yào mǎi?)