Conditional sentences – type III

1. Use

It is impossible to fulfil a condition which is given in the if-clause.

2. Form

if clause main clause
Past Perfect would + have + past participle
could + have + past participle
might + have + past participle

3. Examples

if clause main clause
If I had studied, I would have passed the exams.
If I had studied, I could have passed the exams.
If I had studied, I might have passed the exams.

The if-clause can be at the beginning or at the end of a sentence.

if clause main clause
If I had studied, I would have passed the exams.
main clause if clause
I would have passed the exams if I had studied.