1 jimmy---(collect)stamps for ten  years. He has a lot of stamps mow.
2  What do you need ---(buy)?
3ALL OF us watched the kite ---(hit) the piayground gently.
Afriend of EARTH  MUST(look after the environment)括号提问
-------must a friend of Earth -----?.

儿子作的；
1. Jimmy has collected / 或has been collecting stamps for ten years. He has a lot of stamps now.
2. What do you need to buy?
3. All of us watched the kite hit/  或hitting the ground gently.
4.What must a friend of Earth do?.