1. I don't buy it because I don't have enough money.
→ If I had enough money, I would buy it.
2. I didn't buy it because I didn't have enough money.
→ I would buy it if I had enough money.
3. There was a test yesterday. I didn't know that, so I didn't study for it.
→ If I had known there was a test yesterday, I would have studied for it.
4. I'm busy right now, so I can't help you.
→ I could help you if I wasn't busy right now.
5. He's very thin, that's why he feels so cold.
→ If he wasn't thin, he wouldn't feel so cold.
6. I didn't eat breakfast several hours ago, so I am hungry now.
→ If I had eaten breakfast several hours ago, I wouldn't be hungry now.
7. If John had played for our football team, we would not have lost the game
→ Unless John had played for our football team, we would have lost the game
8. If I won a big prize in a lottery, I'd give up my job.
→ If I had won a big prize in a lottery, I would have given up my job.
9. If you don't like this one, I'll bring you another.
→ Unless you like this one, I'll bring you another.
10. I'll only help you if you promise to try harder.
→ Unless you promise to try harder, I'll help you.
11. If she doesn't work harder, she'll lose her job.
→ She'll lose her job if she doesn't work harder.
12. You can use my car but have to keep it carefully.
→ Provided can you use my car, but have to keep it carefully.
13. If the work is finished by lunch, you can go home.
→ Get the work finished by lunchtime and you can go home
14. Keeping calm is the secret of passing your driving test.
→ As long as you keep calm, you will pass your driving test.

@ `Ly`

1. If I had enough money,I would buy it.

2. I would have bought it if I had had enough money,

3.If I had known the test yesterday,I would have studied for it.

4.I could help you if I wasn't busy right now.

5.If he wasn't so thin,he wouldn't be cold.

6. If I had eaten breakfast several hours ago, I wouldn't be hungry now.

7.Unless John had played for our football team,we would have lost the game.

8.Unless I won a big prize in a lottery, I wouldn't give up my job,

9.Unless you like this one, I'll bring you another.

10. Unless you promise to try harder,I won't help you.

11. She'll lose her job unless she works harder.

12. Provided to keep it carefully,you can use my car.

13. Get the work finished by lunch and you can go home.

14. As long as keep calm,you will pass your driving test