有一长方体游泳池，长80米，宽50米，深2米．请根据这些信息解决下面问题：

①这个游泳池占地面积是多少平方米？

②这个游泳池的底面和四周贴白色的瓷砖，瓷砖的面积是多少平方米？

③游泳池每日凌晨换水，现在水深1.4米，用每分钟排水40立方米的水泵向外排水，需几小时排完？

根据句意和汉语注释，写出单词的正确形式。

1. Tim's brother is so _____ (care) that he often forgets to do his homework.

2. Those _____ (visit) will stay in our school for two days.

3. It's very important for us to keep _____ (save).

4. They were too tired to walk any _____  (far).

5. Mary can learn Japanese by _____ (she).