1 . —Why do you look sad?
—There are so many problems remaining ___________.（settle）

2 . I couldn't take a risk ________ (leave) him alone even for a short time.（所给词的适当形式填空）

3 . I regret to inform you that your brother is just the one we’ll get someone ________ (replace). （所给词的适当形式填空）

4 . With an aim______(achieve), he applies his mind in going over the lessons. (所给词的适当形式填空）

5 . 语法填空
1. The violin will have to be tuned before it _________ (play).
2. There are a few books on the shelf. But only one of them is worth _________ (read) .
3. She worked late into the night, _________ (prepare) a long speech for the president.
4. Stop running and you will feel your heart _________ (beat) .
5. Once _________ (see), it will never be forgotten.
6. He will not come unless _________ (invite).
7. Mr. Brown came in__________(follow) by two students.
8. We agreed _________ (meet) here but so far she hasn’t turned up yet.
9. The missing boys were last seen _________ (play) near the river.
10. —The light in the office is still on.
—Oh, I forgot _________ (turn) it off.

6 . 语法填空
（1）Modern method of ftracking polar bear populations have been employed only since the mid-1980s, and are expensive________(perform) consistently over a large area.
（2）Once his message was delivered, he allowed me__________(stay)and watch.
（3）You don’t have to run fast or for long______(see) the benefit.
（4）Fat and salt are very important parts of a diet. They are required________(process) the food that we eat, to recover from injury and for several other bodily functions.