根据下列句子及所给汉语注释或通过上下文，写出空缺处各单词的正确形式。每空只写一词

1. Peter is the_______（聪明）student in our class.

2．-How many_______（金鱼）do you have?  -Five.

3. Someone_______（敲）at the door just now. Go and open the door.

4. My dog never_______（叫）at others. It is friendly.

5. I'm very_______（友好的）to my friends and I often help them.

6．It's_______（必要的）to listen to the tape every day.

7. If you don't_______（理解）me. I'll say it again.

8. There is a picture at the_______（底部）of the page.

9.-You'd better keep the window_______ .It's hot in the room.-OK.I will open the window.

10. -How is your cat?-She is quite_______ and can't do any tricks.