1. If he had answered the question , he wouldn't have failed the exam 

2. If I hadn't been busy , I would have phoned you

3. If we hadn't stayed up late last night , we wouldn't have been tired

4. If they hadn't been slow , they would have won the match 

5. If I had had an umbrella , I would not have got wet

6. If I had met her , I would have given her your letter

7. If she hadn't been too weak , she could have taken exercise

8. If he hadn't spoken clearly , people would have understood him

9. If Peter hadn't been very nervous , he wouldn't have failed the driving test

10. If he hadn't got up late , he wouldn't have gone to class late

1.He couldn't answer the questions, so he failed the exam.
-> If he had answered the questions, he would not have failed the exam.
2. I didn't phone you because I was very busy.
-> If I had not been busy, I would have phoned you.
3. We stayed up late last night and we were so tired.
-> If we had not stayed up late last night, we would not have been so tired.
4. They were too slow, they couldn't win the match.

-> If they had not been too slow, they could have won the match.
5. I didn't have an umbrella and so I got wet in the rain.
-> If I had had an umbrella, I would not have got wet in the rain.
6. Because I didn't meet her, I didn't give her your letter.
-> If I had met her, I would have given her your letter.
7. She were too weak, she couldn't take any exercise.
-> If she had not been too weak, she could have taken some exercise.
8. People didn't understand him because he didn't speak clearly.
-> If he had spoken clearly, people would have understood him. 
9. Peter was very nervous and failed the driving test.
-> If Peter had not been very nervous, he would not have failed the driving test.
10. He went to class late because he got up late.

-> If he had not got up late, he would not have gone to class late.

#TIB