As,whenandwhileare conjunctions. In some usesas, whenandwhilecan mean the same, but they can also have slightly different meanings. We use them to introduce subordinate clauses.
We can useas, whenandwhileto mean ‘during the time that’, to connect twoevents happening at the same time:
Another coach-load of people arrivedaswe were leaving.
We often use them with the past continuous to refer to background events:
Whenthe men were out working in the field, I helped with milking the cows, feeding the calves and the pigs.
Whilehe was working, he often listened to music.
We can put clauses withas, whenandwhilebefore or after the main clause. When they come before the main clause, we use a comma:
Asshe was leaving the court, a crowd of photographers gathered around her.(before the main clause, followed by a comma)
Steven was very unhappywhenthings weren’t going well for him.
Lucy came into the roomwhilehe was waiting.
As
We can useasto introduce two events happening at the same time. Afteras, we can use a simple or continuous form of the verb. The continous form emphasises an action that interrupts or occurs during the progress of another action:
Asshe walked to the door, she thanked them for a lovely dinner.
Asthey were signing the contract, they noticed that a page was missing.
When
We can usewhento introduce a single completed event that takes place in the middle of a longer activity or event. In these cases, we usually use a continuous verb in the main clause to describe the background event:
He was walking back to his flatwhenhe heard an explosion.
Dependingon the context,whencan mean ‘after’or ‘at the same time’.
| whenmeaning ‘after’ |
| whenmeaning ‘at the same time’ |
See also:
Conditionals
We often usejustwithwhenorasto express things happening at exactly the same time:
The phone always ringsjust whenI’m closing the front door.
She was a brilliant gymnast, but she had a terrible accident in 1999,just asher career was taking off.
Whileandas
We can usewhileorasto talk about two longer events or activities happening at the same time. We can use either simple or continuous verb forms:
We spent long evenings talking in my sitting-roomwhilehe played the music he had chosen and explained his ideas.
We were lying on the beach sunbathingasthey were playing volleyball.
See also:
As
While
Whenandwhilewithout a subject
We can usewhenandwhilewithout a verb, or without a subject + auxiliary verbbe:
Go past the village signpost and you get to a church.Whenthere, take the next turning right.(formal)
He read his bookwhilewaiting for the bus.(while he was waiting)
We can’t useasin this way:
We ate our sandwichesaswe walked around the park.
Not: …as walking around the park.
See also:
When
While