A poster from the film, If… by Lindsay Anderson, an allegorical story where school students take over the school.

A Conditional is a kind of sentence‏‎ which uses a word such as if. It talks about situations which are not real and imagines what might happen.

There are 3 main types of conditional sentences each used in a slightly different situation.

First Conditional

We use the First Conditional to talk about possible situations in the future. These could easily happen and most likely will.

If you go out in the rain, you will get wet.

If you lift that heavy weight alone, you will hurt your back.

To make the first conditional we use two clauses‏‎. The if-clause is in the present tense, the conditional clause‏‎ uses will and the infinitive:

if + {present} | will + {infinitive}

There are two clauses: the if-clause can come first or second. When it comes first, we usually put a comma between the two but it’s not necessary if the if-clause comes last:

If you leave now, you will catch the train.

You will catch the train if you leave now.

Second Conditional

We use the second conditional to talk about possible but unlikely situations in the future and whether they will happen or not, or we can use it to describe imaginary present situations:

If you met the President, what would you say?

If you had a million dollars, what would you do with it?

To make the second conditional we use two clauses. The if-clause is in the past the conditional clause uses would and the infinitive:

if + {past} | would + {infinitive}

If you wrote a bestseller, you would make lots of money.

If I saw a lion, I’d run as fast as I could!

See the main article, Second Conditional.

Third Conditional

We use the third conditional to talk about situations in the past which cannot be changed; we talk about how the results might be different:

If Beckham had scored, Real Madrid would have won the match. (But Beckham did not score and Real Madrid lost.)

If I had studied harder, I would have passed my exam. (But I didn’t study, so I failed.)

To make the third conditional we use two clauses. The if-clause is in the Past Perfect and the conditional clause uses would have and the past participle‎:

if + {past perfect} | would have + {past participle}

If Blucher had not arrived, Napoleon would have won at Waterloo.

If I hadn’t gone to the dance that night, I wouldn’t have met your mother!

See the main article, Third Conditional.

See Also

First Conditional or Second Conditional – sometimes there’s a choice which to use.