用所给词的适当形式填空。
1. You should pay more attention to(practice) your spoken English.
2. Believe nothing he tells you! Everyone knows how(honest) he is!
3.(what) others say to you, it's better to try it yourself.
4. Everybody is supposed to know the(important) of keeping our environment clean.
5. Tom introduced(he) to us at the beginning of the party.
6. Look! The man must(run) for exercise. He does that every day on time.
7. The cat ate some of the bread, and the rest(be) still on the table.
8. The mountains(cover) with trees many years ago.
9. He pretended(begin) doing his homework when I came in.
10. Sorry, I can't get the(pronounce) right.