Adverbial Clauses of Time

An adverb clause of time shows when something happens. It is usually introduced by time adverbs. Examples are: before, after, as, when, while, until, as soon as, since, no sooner than, as long as etc. Note that all adverb clauses are subordinate clauses. They cannot stand on their own and must be attached to an independent clause.

Read the examples given below.
I always take a bath before I go to bed.
Will you wait here until I am ready?
I was not at home when he came to see me.
Do not disturb me when I am busy with my work.
As soon as she finished that project, she started working on the next.
After I have finished my work, I will accompany you to the park.

Notes
An adverb clause of time can come before or after the main clause. When it comes before the main clause, we usually separate it with a comma. Commas are not necessary when the adverb clause goes after the main clause.
Whenever I think of her, my eyes get misty.
My eyes get misty whenever I think of her.

Verbal Tense
If you are talking about something that is yet to happen in the future, use a present tense in the adverb clause and a future tense in the main clause.
I will start when I am ready. (NOT I will start when I will be ready.)
I will not go until I get my money back. (NOT I will not go until I will get my money back.)