1. 根据句意及所给汉语提示，写出句中所缺单词。

1. （1） （机器人）will help us a lot.

3. （2） There are many tall （树）in the park.

5. （3） Everyone hopes there will be less （污染）in the future.

7. （4） Mary wrote down her address on a piece of （纸）．

9. （5） There are （更少的）students in Class One than in Class Two.