http://www.cecytebc.edu.mx/HD/archivos/antologias/ingles_lll.pdf

http://www.englishclub.com/grammar/verbs-conditional_4.htm

 

Third Conditional:

With the third conditional we talk about the past. (The first
and second conditionals talk about the future).
⇒ We talk about a condition in the past that did not happen. That
is why there is no possibility for this condition.
⇒ The third conditional is also like a dream, but with no
possibility of the dream coming true.

Last week you bought a lottery ticket. But you did not win.
⇒ We use WOULD HAVE + past participle to talk about the
impossible past result.
⇒ The important thing about the third conditional is that both
the condition and result are impossible now.
condition result
Past Perfect WOULD HAVE + Past Participle
If I had won the lottery I would have bought a car.

IF condition result
past perfect WOULD HAVE + past participle
If I had seen Mary I would have told her.
If Tara had been free yesterday I would have invited her.
If they had not passed their exam Their teacher would have been sad.
If it had rained yesterday would you have stayed at home?
If it had rained yesterday what would you have done?

result IF condition
WOULD HAVE + past participle past perfect
I would have told Mary if I had seen her.
I would have invited Tara if she had been free yesterday.
Their teacher would have been sad if they had not passed their exam.
Would you have stayed at home if it had rained yesterday?
What would you have done if it had rained yesterday?
Modals can be used in the result clause to indicate past hypothetical possibilities,
permission and advice.
If he had known, he could have given you a hand.
If you hadn’t prepared, you should have told the professor.

Second and Third Conditional Practice
Look at the following sentences concerning the problem of debt relief and complete if
the sentences they can be either second or third conditional. It is possible that the
sentence is a mix of the two.
1. If these countries _____________ (not be) so poor, they _____________ (not
need) to borrow money.
2. Many of these banks _____________ (not lend) all this money if they
_____________ (know) there would be all these problems now.
3. If some of the poorer countries _____________ (have) less corrupt governments
during the 60’s and 70’s, they _____________ (not face) these difficulties now.
4. The money _____________ (can) be spent better if they _____________ (not
buy) so many unnecessary things for the house.
5. There _____________ (not be) such a debt problem if the world _____________
(be) a fairer place!
6. If the western states _____________ (charge) less interest, the amount owed by
the poorer states _____________ (be) a lot less.
7. Some people say that if the colonial powers _____________ (take) less in the
last couple of centuries, these poor nations _____________ (be) far richer now.
8. If the debt _____________ (be) written off, it _____________ (may not be) the
end of the problem.
9. What _____________ (happen) if we _____________ (not loan) all this money
in the beginning?