Third conditional

CONDITIONAL 3

The 3rd Conditional is used to talk about situations in the PAST.

Here is an example of a situation where it is used:

Last week, my sister's car wouldn't start and she had to take the bus to work. I didn't know about it, so I didn't give her a ride to work. I saw her yesterday, and she told me about her problem with the car. When I saw her, I said:

If I had known your car wouldn't start, I would have given you a ride to work.

Here, I am talking about what I would have done in the past if I had known about her car. But the real situation was that I didn't know.

Here is another example:

Yesterday, my friend stopped by my apartment at dinner time to visit. I didn't know he was coming, so I didn't cook dinner before he came. I said:

If I had known you were coming, I would have cooked dinner.

Again, I am talking about what I would have done in the past if I had known he was coming. But the real situation was that I didn't know.

The 3rd Conditional is formed like this:

IF + PAST PERFECT, WOULD + PRESENT PERFECT

NOTE:  COULD HAVE or MIGHT HAVE are also possible in these situations:

If I had known you needed money, I could have given you some.

We could have gone to the park if the weather had been better.

If you had known sooner, you might have been able to help.

We might have come to your party if we had received the invitation earlier.