根据句意和所给的首字母提示，补全句子中的单词。

1. If there were more trees on the earth, there would be l____ pollution.

2. I don't like eating lemon. It t____ too sour.

3. The injured people were taken to hospital i____ after the accident.

4. Look, the expression on his face s____ that something bad must have happened to him.

5. According to an ancient Chinese legend, the emperor Shen Nong d____ tea.

把一些图书分给某班学生阅读，如果每人分3本则剩余20本；如果每人分4本，则还缺25本．这个班有多少学生？