When, while, before, after, until, as soon as
In English, we use time expressions like “when, while, before, after” to explain the sequence of events.
When: at the time, during the time
(While “when” used to mean “when?” as a question, here, we will use it as a conjunction to combine two events happening at the same time.)
I will visit you when you finish your duty. (Present)
I was having dinner when you phoned me. (Past)
I was watching an exciting match when the earthquake happened. (Past)
While: during the time
(While connecting two events that occurred simultaneously)
While I was washing my car, the earthquake happened.
While it was snowing, we went outside.
While you are here, can you help me finish my project?
While he was having breakfast, the phone rang.
While I was shopping yesterday, I saw my old friend that I hadn’t seen for years.
While you are here, please watch out my car, then I will be back in a few minutes.
(We can also use “till” instead of “until” when specifying a time limit.)
We will stay in this hotel until/till next Saturday.
We played football until it got dark.
Until you arrive here, we’ll have finished all the work.
(Specifying an action to take place before another.)
Before you start doing warm-up, you should eat less.
Before you leave, you must pay your bill.
Before she got out of the store, she saw the thief stealing a T-shirt.
(Referring to an action happening subsequent to another.)
After Jill arrives, she will phone us.
After you finish your business, please pick me up from 5th Street.
After the rain started, we went outside to play soccer.
After the earthquake happened, all the people in town were running around the streets. But suddenly it stopped, and everybody calmed down.
As soon as
(Indicating something happening immediately after another.)
As soon as she made tea, she called us.
As soon as she had dinner, she went outside for shopping.
As soon as she is coming, she started to prepare something to eat for her family.