1.If we don't protect the environment, we will destroy ourselves.
2. If she isn't more hard-working,she will get low marks.
3.If he doesn't listen to his parents,he will fail.
4. They have watched the movie for one hour.
5.He has not cried for ten years.
6.He hasn't gone abroad before.
7. She has driven for 1 month.
8.We have eaten since it started to rain.
9.Nam is interested in watching television.
10.I have never talked to the foreigner before.
Chúc bạn học tốt!!!!!!
