1. (2018·深圳模拟) 听下面一段对话或独白，录音播放两遍。请根据所听内容回答问题。

1. （1） Why was life hundreds of years ago much harder than it is today?
3. （2） How many kinds of pollution are mentioned?
5. （3） What pollutes the air every day?
7. （4） What must factories do before the waste water is poured out?