水是我们人类生活重要的物质之一，自然界中的水都含有一些杂质，生活用水常常需要净化处理，净化水的操作有：①静置沉淀；②蒸馏；③吸附等，其中单一操作相对净化程度离高的是______（填序号）．

用所给词的适当式填空

1. Forget all the ________ (pleasant) things, and  try to stay happy.

2. His father is head of one of the biggest ________ (company).

3. You are too heavy. Eat ________ (little) and exercise more, and you will be healthier.

4. What will the weather ________ ( be)  like   tomorrow?

5. —________  the Browns ________ ( go)  to Shanghai for vacation?

    —Yes, they will.