Grammar

English conditionals: grammar rules, examples

►The zero conditional describes situations that are always true. If has the same meaning as when or whenever.

If I go to school, I get up at seven. (Whenever I go to school I get up at the same time.)

If you park your car on double yellow lines, you pay a fine. (Whenever you park illegally, you pay a fine.)

We use the present simple tense in both the main clauses and the if clauses.

► The first conditional sentences are used to speculate about possible situations that can really happen at present or in future.

We do not use will in an if clause to describe future activities (compare it to time clauses).

If he studies hard, he'll pass the exams. If we catch the 10.15 train, we will arrive on time. If you don't get the ticket, what will you do?

We make if clauses with if + present tense and main clauses with will + bare infinitive. 

► In the second conditional sentences we speculate about situations that will probably never happen at present or in future.

If I had more time, I would help you. (But I am not free at the moment. I can't help you).

If I won a million dollars, I would start a business of my own. (But I know that it is not realistic.)

We make if clauses with if + past tense and main clauses with would + bare infinitive.

Note: the verb to be can be specific in the if clause.

If I were rich, I wouldn't work. If he were younger, he would marry her.

(But was is also possible: If I was rich, I wouldn't work. If he was younger, he would marry her.)

But: If I were you, I wouldn't do it. (In this expression, were is much more usual than was.)

► The third conditional sentences always refer to the past. We speculate about situations that happened or did not happen in the past.

If I had won a million, I would have started a business of my own. (But I didn't win anything.)

If he had met her, he would have told her. (Unfortunately, he didn't meet her.)

If we hadn't practised, we wouldn't have won the match. (But we practised and won.) 

We make if clauses with if + past perfect and main clauses with would + perfect infinitive (have + past participle).

But we can also combine other verb structures in third conditional sentences.

We didn't save any money. If we had saved some money, we might have bought the house.         

She wasn't there and I wasn't sitting next to her. But if she had been there, I would have been sitting next to her.                                                                                  

I was looking at the trees when I fell off the bike. If I hadn't been looking at the trees, I wouldn' t have fallen off the bike.