Giải giúp mình với ạ. Đang cần gấp. Rõ ràng nha

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`