when

when [ wen, hwen ] function word ***

When can be used in the following ways:

as a conjunction (connecting two clauses):

When he saw me, he waved.

as a question adverb (introducing a direct or indirect question):

When should we meet?

Do you know when these houses were built?

as a relative adverb (referring back to a noun and introducing a relative clause):

I remember the day when the war began. (introducing a clause that is the subject, object, or complement of another clause):

My proudest moment was when I received the poetry prize.

1. ) at what time or in what situation

a ) used for asking at what time something happens:

When will we know our test results?

When did the trouble start?

I asked him when he was going to start work.

You'll get your money back. Yes, but when?

since when: Since when have you been in charge of the project?

b ) used for asking in what kind of situation something happens:

When should I end a letter with Sincerely yours?

When is it OK to hug someone that you've just met?

c ) used when someone knows or says at what time something happens, or in what situation it happens:

He didn't say when they would leave.

It is important to know when you have had enough to drink.

2. ) at the time that something else happens

a ) as soon as another action or event has finished:

When it stops raining, I'll show you the garden.

b ) at the same time as something else:

I always wear a hat when I work in the garden.

when doing something: She was often nervous when facing the camera.

c ) at a point during the time that something else is happening:

She claims she was at a friend's house when the shooting took place.

3. ) => NOTE at a particular time or in a particular situation used for talking about a particular time or situation:

The biggest surprise for Josie was when she was chosen as team captain.

the time/day/year etc. when: Do you remember the time when we took your mother camping?

There are some days when everything seems to go wrong.

4. ) used for introducing surprising information used for introducing a situation that makes someone's action or behavior seem surprising:

He went on protesting his innocence when he was obviously guilty.

Why does she always drive to work when she could easily take the train?

5. ) used for describing a general situation used for making a general statement about something that is always true or correct:

We use an when the next word begins with a vowel.

Tonic water makes a refreshing drink when served with ice and lemon.