根据句意及汉语或首字母提示，用该单词的适当形式填空。

1. When we go to the desert, we'll see little v________ there.

2. May Day and National Day are both p________ holidays

3. I sat down to write my essay, but I found it was completely without i________.

4. Parents should e________ their children to behave well.

5. He is a busy teacher with little s________ time.

6. It was too late to s________ the dog. It died at last.

7. It's harmful for the villagers to eat or drink the p________ food or water.

8. We should protect the e________ and make our world more and more beautiful.

9. We are lucky to live in the new________ (社会), so we must study hard.          

10. Look at this, it is a________ (模型) of a plane.