定义：一个数集的和就是这个集合中所有元素的和．设S是由一些不大于15的正整数组成的集合，假设S中的任意两个没有相同元素的子集有不同的和，则具有这种性质的集合S的和的最大值为（　　）

A．76

B．71

C．66

D．61

根据所给首字母及汉语提示完成下列单词。

1. S______ say that seventy-four different kinds of living things go extinct every day.

2. Help y_______ to some fruit, children.

3. Can you p______ it to me? I don't think you are right.

4. China is a country with a rather long h_______.

5. It's p_____ to jog in early morning.

6. The r_____ why so many people caught the disease is still not clear.

7. People and the other animals can't live w_______ air or water.

8. Water is a l______, but you can change it into solid.

9. Ms. Li always tries new teaching m _______ in her English class.

10. The shop sells f_________ like desks and chairs.