单选题
Sleep is something we generally connect with living things. Of course, it is true that a tot of animals sleep, but scientists are not certain that primitive (原始的) forms of animal life like worms ever really sleep. On the other hand, animals such as bears sleep for 4 or 5 months every year. The amount of sleep that a human being needs depends on age, tile individual and possibly race. For example, doctors think pre-school children need between 10 and 12 hours a night; school children between 9 and 11 hours; and adults between 7 and 9 hours. There are cases of old people who only sleep between 2 and 3 hours a day and continue to be active and healthy. The sleep requirements Of different races also appear to be different. Japanese people, for example, sleep fewer hours than Europeans. It is not known whether mental activity (except dreaming) occurs when a person is asleep. However, it is certainly true that some people can wake up at a particular time. There are also stories about scientists who solve difficult problems during sleep, because their subconscious (潜意识的) minds continue working on the problem. Some types of nightmares are quite common: the dreamer is falling from a tree; or an animal is running after him. Some people say these two occur because man's ancestors (祖先) lived in trees and were in constant danger from wild animals.
单选题
Which of the following is NOT TRUE? A. We don't know if the worms really sleep or not. B. Old people only sleep 2 or 3 hours a day. C. People of different ages sleep different hours. D. People of different races sleep different hours.
【正确答案】
B
【答案解析】本题为否定命题。 There are cases of old people who only sleep between 2 and 3 hours a day and continue to be active and healthy, 不能代替所有老人的睡眠时间。
单选题
The stories about scientists who solve difficult problems during sleep show that ______. A. they are still working when they are sleeping B. difficult problems will become easier in one's sleep C. a person's mind can still be active when he is asleep D. all difficult problems can be worked out during sleep
【正确答案】
C
【答案解析】本题为细节题，从文章第三段because their subconscious(潜意识的)minds continue working on the problem. 可得到正确答案。
单选题
We can infer from the text that ______. A. all living things sleep B. some people can wake up on time without being called C. old people usually sleep nine or eleven hours a day D. we are sure that our minds are not going when we are asleep
【正确答案】
B
【答案解析】本题为推理性命题，所涉及的细节分布在全篇。从However, it is certainly true that some people can wake up at a particular time. 也可以看出答案。
单选题
Some common nightmares are said to be connected with man's ______. A. experience B. history C. ancestors D. subconscious minds
【正确答案】
C
【答案解析】本题为细节题，从最后一段中Some people say these two occur because man's ancestors lived in tress and were in constant danger from wild animals. 可以看出答案。