Adverbial clauses of time

"As," "when," and "while" can all be used to talk about something that happens simultaneously with something else:

As/When/While Miguel was eating, the doorbell rang.

When to Use "When"

Use "when" to introduce a clause that refers to an event happening at the same time as a longer event in the main clause:

∗They were playing in the garden when they heard a scream.

"When" is also used to describe the circumstances in which the main event happens:

∗When they are fully grown, these snakes can be over two meters long.

"When" can mean "every time":

∗I still feel tired when I wake up in the morning.

"When" is preferred when one event immediately follows another, particularly if one causes the other:

∗You’ll see my house on the right when you cross the bridge.

When to Use "As"

"As" is preferred to indicate that as one thing changes, another thing changes at the same time:

∗As the cheese matures, its flavor improves.

"As" can also be used to describe simultaneous actions, often with a continuous tense:

∗As the cheese is maturing, its flavor improves.

When to Use "While"

"While" is often used in informal speech to indicate two longer actions happening at the same time:

∗I went shopping while Liam cleaned the house.

Use "while" or "when" (instead of "as") to avoid ambiguity, where "as" could mean "because":

∗While you were playing golf, I went to the cinema. (As you were playing… could mean Because you were playing…)

Before, After, and Until

"Before" and "after" are used to indicate that one event happens earlier or later than another event:

∗I put on my coat before I went out.

∗The message arrived after I’d left.

"Until" is used to talk about an action that continues to a specific time and then stops:

∗They sat on the beach until the sun sank below the horizon, and then they went home.

"Until" is also used when the adverbial clause describes the result of an action in the main clause:

∗He cleaned his shoes until they shone.

Hardly, No Sooner, Scarcely

"Hardly," "no sooner," and "scarcely" are used to describe events that happen immediately after one another:

∗The concert had hardly begun before all the lights went out.

∗I had no sooner lit the barbecue than it started to rain.

Try this exercise to test your grammar.

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