"When", "while", "as" are conjunctions that connect two sentences.

We use "when", "while", and "as" to talk about two things that happen at the same time.

Use "while" and "as" to emphasize that the two actions were happening at exactly the same time. They can also be used to mean "during that time".

"While" is mostly used with the past continuous verb tense, and "as" is used with both the past tense and past continuous verb tense.

Event 1A + as/while + Event 1B

• She was studying while I was watching TV.
• They are laughing while I am working hard.
• The baby was crying while we were leaving.
• She looked at me as she walked away.
• They never looked back while they were driving away.
• She was crying as she was leaving.
• He was laughing as he stole the car.
• She watched my dogs while I was on vacation.
• He helped cover my work while I was sick.

We can also put "as" and "while" at the beginning of a sentence.

As/While + event 1A, + event 1B

Put a comma after the first event when writing.

• As she was looking for her keys, her brother came into the room.
• While we were talking, she said something strange.

We can always replace "while" and "as" with "when".

• She was studying when I was watching TV.
• The baby was crying when we were leaving.
• She looked at me when she walked away.
• They never looked back when they were driving away.

We can use "when" at the beginning or middle of a sentence.

Action/Event + when + time/action

Both parts should be sentences.

• She was surprised when she came.
• She loved to dance when she was young.
• My mother makes me chicken soup when I am sick.
• We love to play outside when it snows.
• Everybody left when the game was over.

When + time/action, + action/event

Use a comma to separate the two parts when you are writing.

• When she is ready, we will leave.
• When the game is over, we will get some dinner.
• When the company went bankrupt, he had to find a new job.

"When" is used in many situations.

1. Use it to tell general truths or things that usually happen

• I drink orange juice when I am sick.
• She goes camping when she has time.
• When she wakes up, she makes breakfast for her family.
• When you study hard, your English improves faster.

2. Use it to tell an action or event that happened at the same time as a longer event.

• I went out when it was raining.
• She helped me when I was working overtime.

3. Use it talk about periods of time in the past.

• I read this book when I was in high school.
• She loved this movie when she was young.
• When we were dating, we often went to dinner and a movie.

4. Sometimes, "when" has the same meaning as "after".

• She cried when she heard the news.
  (=She cried after she heard the news.)


• We will leave when we finish.
  (=We will leave after we finish.)

5. Use it to tell the time or condition that a future action will be done or happen.

• I will get a job when I finish school.
• I will buy a car when I am rich.
• When she is ready, she will come.

5. "If" and "when" are very similar.

To explain it simply, use "if" to talk about a possible or unreal situation. We are not sure if it will happen or not, we are just thinking about it as a possibility.

Use "when" to talk about a time of a future situation that you are certain will happen.

• If she comes, I will talk to her.
  (In this sentence, we are not sure whether she will come or not)


• When she comes, I will talk to her.
  (In this sentence, I know she is coming and I am certain of it. I am just waiting for this event to happen.)

Learn to speak better English and improve your English grammar by simply doing this basic practice exercise. First, complete the sentences with your own answers, and then practice making your own sentences. Finally, try using this grammar in real life.

She was _______________ while I was _______________.
She _______________ while I was away.
They _______________ while I was on vacation.
It was raining while he was _______________.
He said _______________ while I was leaving.
As I walked in the door, _______________.
She started to cry as _______________.
As she was leaving, _______________.
I _______________ when I was young.
When it is too cold, I _______________.
She _______________ when it is raining.
I like to _______________ when I have free time.
My family used to _______________ when I was a child.
My friends and I _______________ when we finished school.
When I have some free time at work, I _______________.