Study the rules and complete them
Look at the sentence:
If I go to London, I will visit the British Museum.
In this sentence:
- If I go to London is the if-clause (conditional clause);
- I will visit the British Museum is the main (result) clause.
The sentence has a conditional clause. It starts with if.
Look at the next sentence:
When I am 18, I will buy a car.
In this sentence:
- When I am 18 is the time clause;
- I will buy a car is the main clause.
The sentence has a time clause. Time clauses can start with when, before, after, as soon as, until, till.
Present Simple and Future Simple
In conditional (if-) clauses and time clauses, we use[Present Simple|Future Simple]. In main clauses, we use [Present Simple|Future Simple].
Conditional clause / time clause |
Main clause |
if / when / before / after / as soon as / until / till + Present Simple |
Future Simple |
If I come late, |
my boss will be angry |
When Sue comes, |
we dinner |
As soon as I Jim, |
I will tell him the news |
Punctuation
If a conditional (if-) clause or a time clause comes before the main clause, there [is|isn't]a comma (,) between the two clauses:
- If I go to London, I will see Big Ben.
- When I am 18, I will buy a car.
- After you finish your test, you will go home.
If a conditional (if-) clause or a time clause comes after the main clause, there [is|isn't]a comma (,) between the two clauses.
- I will see Big Ben if I go to London.
- I will buy a car when I'm 18.
- You will go home after you finish your test.