If I'd known you had a problem, I would have helped you.
If Paul hadn't gone to Brazil, he wouldn't have met his wife.
Would you have gone to the party if you'd known Lisa was there?
You wouldn't have lost your job if you hadn't been late every day.
If I’d known you were ill, I would have come to see you.
If the weather had been better we would have stayed longer.
If I hadn’t stopped to get petrol, I wouldn’t have been late.
We would have missed our flight if it hadn’t been delayed.
It would have been much quicker if we’d taken a taxi.
She wouldn’t have found out if you hadn’t told her.
The tickets would have been cheaper if we’d booked them earlier.
If you hadn’t done your homework so quickly, you wouldn’t have made so many mistakes.
I would have lent you some money if you’d asked me.
We normally use third conditional sentences to talk about hypothetical / imaginary situations in the past, i.e. how things could have been different in the past.
Compare:
Yesterday I got up late and missed my train.
(the real situation)
If I hadn't got up late yesterday, I woudn't have missed my train.
(hypothetical or imaginary past situation)
To make a third conditional, we use:
If + past perfect and would have + past participle
NOT If I would have known you had a problem...
The contraction of both had and would is 'd.
If I'd known you had a problem, I'd have helped you.
We can use might or could instead of would to make the result less certain.
If she'd studied harder, she might have passed the exam.
Exercise a
Billy wouldn't have injured his head if he'd worn his helmet.
If I hadn't seen the speed camera, I woudn't have slowed down.
Jon might have got the job if he'd been on time for his interview.
She would have hurt herself badly if she'd fallen down the stars.
If Katy and Luke hadn't caught the same train, they woudn't have met.
What would you have studied if you'd gone to university?
How would you have got to the airport if the trains had been on strike?
If you'd worn a warmer coat you woudn't have caught a cold.
Your parents would have enjoyed the trip if they'd come with us.
Woud you have been annoyed if she'd told you the truth?
Exercise b
If Tom hadn't gone to the university. he wouldn't have got a job with that company.
If you hadn't taken me to the station, I would have missed my train.
We wouldn't have won the match if the referee hadn't given us a penalty.
You would have enjoyed the weekend if you had come with us.
If I hadn't bought the theatre tickets online, they would havebeen more expensive.
Mike would have forgotten his wife's birthday if she hadn't remind him.
If the police have arrived five minutes later, they wouldn't have caught the thief.
If you hadn't lent me the money, I wouldn't have been able to go away for the weekend.
That girl would have fallen in the river if you hadn't caught her arm.
We wouldn't have found the hotel if we hadn't seen the signpost.
If I had known about the job, I would have applied for it.