The time clauses in the English language are introduced by conjunctions such as after, as soon as, before, till, until, when, whenever, while or time expressions such as the minute, the moment etc.
Have you noticed the structure?
When, After, Before, As soon as, Until and If are followed by SIMPLE PRESENT TENSE. The main clauses in these sentences are followed by future ‘will’.
I'll go to the dentist's as soon as I have (no future!) a toothache.
What a mess! Your mother will be angry when she comes back. (no future!)
I'll stay at home until you phone me. (no future!)
WHEN
When I finish writing the reports, I will go out with my friends.
She will move to London when she finds a good job.
When the party is over, my boyfriend will clean the whole house.
Be careful!
If when introduces a noun clause which is the object of a verb, it is followed by a future tense:
I don't know when she will arrive.
I can't remember when the race will start.
You must decide when you will meet them.
In all these sentences the question is: What? not When? (I don't know what, I can't remember what, You must decide what.)
BEFORE
Before I go on holiday, I’ll book my hotel.
He will visit all his relatives before he goes to university.
They won’t transfer any money before they sign the agreement.
AFTER
After her sister prepares dinner, they’ll invite their neighbours.
My boss will buy a new car after he saves enough money.
What will you do after you finish the book?
AS SOON AS
They will go to the beach as soon as they have their breakfast.
All the players in the national team will go on holiday as soon as the Europian Championship is over.
Don’t worry mom. I will phone you as soon as I arrive Paris.
UNTIL
You can go out. I will wait until she calls.
They won’t start the match until the rain stops.
I won’t buy anything new until I pay all my debts.
IF
If I go home early tonight, I will watch the match on TV.
Tim will buy a new laptop if the prices goes down.
If you pass the test, what will you do?
Warning! The subordinate clause can be at the beginning of the sentence!
When tears are in your eyes I will dry them all. (Paul Simon)
As soon as you meet Janet, you will love her.
Until you are eighteen, you will not drive a car.