Question

【题目】We humans spend about one-third of life asleep. Sleep helps us stay healthy, and it also helps our brain remember. Our brains need good sleep to remember what we do and learn during the other two thirds of our life when we are awake. Besides keeping us healthy, some new research shows that a good night’s sleep helps make us more intelligent.

Researcher at the University of Wisconsin-Madison have found that sleep helps improve brain performance by shrinking synapses in the brain. A synapse is the area where cells pass messages to other cells.

Cirelli is a leading scientist at the school’s Center for Sleep and Consciousness. She found that sleep is when the human brain mixes information it has learned while awake into its general collection of knowledge. However, the brain forgets unimportant details. This forgetting is important. It makes space for new learning and new memories.

Cirelli said that the Center’s research began with this hypothesis: We sleep so that our brain can repair and refresh itself. She said the idea seems simple and reasonable. However, testing and discovering how it works has been extremely difficult. Cirelli and Center director Giulio Tononi have been trying to prove the connection between sleep and the brain’s synapses since 2003. Cirelli said the researchers knew that “stronger synapses are also bigger.” So, they began their study by “measuring the size of the synapses” in the brain.

They also knew that during sleep, the brain checks on all its synapses and resets itself for the next day. The team wanted to see if the synapses of the brain are bigger after being awake all day and smaller after a good night’s sleep. Synapses are only about 20-40 nanometers wide. So, the team looked for changes in these already tiny spaces between nerve cells. The team had lo wail until improvements in laboratory technology made it possible to see these tiny changes.

Cirelli says they found that synapse size and strength are upset by being awake and restored by sleeping. She says our synapses shrink as our brains clean themselves during sleep. We wake up refreshed and ready to fill those synapses with new information.

【1】Which of the following statements is true according to the passage?

A. Sleep can only keep us healthy.

B. Sleep can help our brain function better.

C. Sleep can mix all the information.

D. Sleep can take up two-thirds of our life.

【2】What does it refer to in Paragraph 4?

A. The measuring the size of the synapses.

B. The space for new learning and new memories.

C. The way our brain can repair and refresh itself.

D. The connection between sleep and the brain’s synapses.

Answer 1

【答案】

【1】B

【2】C

【解析】试题分析：本文主要讲述了睡眠有助于大脑的收缩，从而改善大脑表现。良好的睡眠除了让我们保持健康，还有助于我们变得更聪明。

【1】B细节理解题，根据文章第一段最后Besides keeping us healthy, some new research shows that a good night’s sleep helps make us more intelligent.可知睡眠除了可以让我们身体健康，还可以有助于我们的大脑变得更聪明，故A描述片面，B正确。根据文章第二段She found that sleep is when the human brain mixes information it has learned while awake into its general collection of knowledge. However, the brain forgets unimportant details可知当人们的大脑把它在清醒时学到的知识混合在一起时，就会产生睡眠，然而，大脑忘记了不重要的细节可知C不正确，根据文章第一句We humans spend about one-third of life asleep 可知我们有三分之一的时间在睡觉，可知D不正确。故选B。

【2】C推理判断题，根据文章第一段内容可知大脑有自己的方式来修复和更新，故选C。