I. 用所给词的适当形式填空。（20分）
1. Bill is ________(tall) than Tom.
2. Helen is the ________ (young) in our class.
3. The boy put on his coat and went to out _______(quiet).
4. Alice felt very _____ (happy) at her birthday party.
5. Which is ____ (far) from us, the Mars or the moon?
