用括号内所给动词的适当形式填空。

1. All of you are very busy ______ (get) for this exam, aren't you?

2. You had better ______ (not hurry). There is still enough time to go.

3. The student ______ (name) Wang Lin is my example in English learning.

4. If you are really tired, you can stop ______ (have) a rest for 10 minutes.

5. When I got home, my pet dog ______ (lie) on the floor, dead.

润滑的意义是什么？常用的润滑方法及应用场合？