I. First conditionals
if clause and main clause
All conditional sentences have two parts: the if clause and the main clause. It doesn’t matter which clause comes first, but when the if clause comes first, we should put a comma after it.
- If it rains, we’ll stay home
- We’ll stay home if it rains.
if + present, future
In the first conditional, the verb in the if clause is present and the verb in the main clause is future (will).
- If you don’t go to sleep, you’ll be very tired tomorrow.
The if clause may have a present or a future meaning, but the verb is always in present (NOT future)
- If you are a good boy tomorrow, mummy will buy you a present. (NOT
If you will be a good boy)
Main clause: will, modal verb, imperative
In the main clause, we can use may, might, can, must, should instead of will.
- If he doesn’t train harder, he may/might lose the championship.
- If your room is tidy, you can leave.
- If you want to lose weight, you must/should eat less sugary things.
Or we can also use an imperative instead of will.
- If you arrive after midnight, ring me on my mobile.
unless = if (not)
We can also use unless in conditional sentences to mean if … (not)
- I won’t go on holiday unless I save some money.
- = I won’t go on holiday if I don’t save some money.
II. Second conditionals
if clause and main clause
We use if + past to talk about an imaginary present or future situation (although the verb is in past, the meaning is present or future). And we use would + infinitive to talk about the result or consequence of that imaginary situation.
- If we had a mansion in the country, we’d go there every weekend.
- Would you travel around the world if you won the lottery?
Comma
When the if clause comes first, we normally put a comma after it. We don’t use a comma when the main clause comes first and the if clause comes second.
- If I won the lottery, I’d buy a mansion.
- I’d buy a mansion if I won the lottery.
unless = if (not)
We can also use unless in conditional sentences to mean if … (not)
- I wouldn’t live in a big city unless I had a lot of money.
- = I wouldn’t live in a big city if I didn’t have a lot money.
would, could, might
In the main clause, we can use could or might instead of would.
- If there was a fire, it would be difficult to escape.
- If you were a bit taller, you could be a basketball player.
- We might save enough money if we both worked overtime.
was or were?
In the second conditional we can use if I/he/she/it were (more formal) instead of if I/he/she/it was.
- If I were/was fit, I would run a marathon.
- We wouldn’t have any problems if he were/was more reasonable.
But we use were (NOT was) when we give advice with the expression if I were you.
- If I were you, I would stay home and rest.
- I wouldn’t pay any attention to what he says if I were you.
