单选题

Air is all around us. It is around us when we walk and play. From the moment we are born, air surrounds us. When we sit down, it is around us. When we go to bed, air is also around us. No matter where we are on earth, air surrounds us. We live in air.
All living things need air. Living things cannot live without air. We can go without food or water for a few days, but we cannot live for more than a few minutes without air. When we are working or running, we need more air. So we breathe faster than usual. When we are asleep, we need less air.

单选题 People can live without food or water for______.

A、

[A] a few months
B、

[B] a few weeks
C、

[C] a few days

【正确答案】 C

【答案解析】[解析] 根据第二段第三句We can go without food or water for a few days…可知我们可以几天不吃饭、不喝水。所以应选C。

单选题 When we are sleeping we______.

A、

[A] need less air
B、

[B] need more air
C、

[C] don't need air at all

【正确答案】 A

【答案解析】[解析] 根据第二段最后一句When we are asleep，we need less air．可知睡觉的时候。我们需要的空气就较少。所以应选A。

单选题 The main idea of this passage is that______. [A] air is much more important to us than food and water [B] air is around us and we can't live without it [C] air is as important to us as food and water

【正确答案】 B

【答案解析】[解析] 通读全文可知这篇文章讲的主要是空气包围着我们和空气的重要性，这就是如果没有空气我们是不能生存的，而不是主要将空气和食物、水做比较。所以应选B。