Question

【题目】The Amazing Brain

Sleep. It’s something we spend about a third of our lives doing, but do any of us really understand what it’s all about?

We all know based on our own experience that when we sleep, it clears our minds, and when we don’t sleep, it leaves our minds murky (昏沉沉的). But when we still haven’t understood why sleep has this amazing function for the mind.

Recently biologists have found that sleep may actually be a kind of design solution to some of the brain’s most basic needs, the way that brain meets the high demands and the narrow margins (范围) that set it apart from all the other organs (器官) of the body. The brain has a large pool of clean, clear fluid (流体) called cerebrospinal fluid. Biologists call it the CSF. The CSF fills the space that surrounds the brain, and wastes from inside the brain make their way out to the CSF, which gets the waste into the blood. What was surprising to them was that the fluid on the outside of the brain didn’t stay on the outside. Instead, the CSF goes into and through the brain along the outsides of the blood vessels (血管), it was actually helping to clear away and clean the waste from the spaces between the brain’s cells (细胞). This only happens in the sleeping brain.

Recent research suggests that what’s happening is that when the brain is awake and is at its most busy, it puts off clearing away the waste from the spaces between its cells until later. When we go to sleep, it gets into a kind of cleaning mode to clear away the waste from the spaces between its cells.

We go to sleep every single night, but our brains never rest. While our body is still and our mind is off walking in dreams somewhere. Like our housework, it’s dirty and a thankless job, but it’s also important. In your house, if you stop cleaning your kitchen for a month, your home will become completely unlivable very quickly. But in he brain, the situation is much more serious because when it comes to cleaning the brain, it is the very health and function of the mind and the body that’s at stake. That is why understanding these very basic housekeeping functions of the brain today may prevent and treat diseases of the mind tomorrow.

【1】What does the underlined phrase “at stake” in the last paragraph mean?

A. in a healthy situation

B. in a dangerous situation

C. in an amazing situation

D. in an unlivable situation

【2】What can we learn from the passage?

A. Sleeping makes our brain feel murky.

B. The CSF can clean the waste in our brain.

C. Our brain can clean the waste at any time.

D. Sleeping makes our brain have a good rest.

【3】What is the main purpose of writing this passage?

A. To teach us how to have a good sleep.

B. To show the new research of our brain.

C. To introduce how CSF works in our brain.

D. To tell us the importance of sleeping.

Answer 1

【答案】

【1】B

【2】B

【3】D

【解析】

本文主要介绍了睡眠能帮助大脑清理垃圾。

【1】词义猜测题。根据But in he brain, the situation is much more serious because when it comes to cleaning the brain可知此处指的是非常严重的，危险的， 故选B。

【2】推理判断题。根据 Instead, the CSF goes into and through the brain along the outsides of the blood vessels (血管), it was actually helping to clear away and clean the waste from the spaces between the brain’s cells (细胞).可知，CSF帮助清理我们大脑里的垃圾，故选B。

【3】推理判断题。根据 Sleep. It’s something we spend about a third of our lives doing, but do any of us really understand what it’s all about?和When we go to sleep, it gets into a kind of cleaning mode to clear away the waste from the spaces between its cells.本文主要是为了介绍了睡眠能帮助大脑清理垃圾，因此是为了告诉我们睡眠的重要性，故选D。

认真阅读题干，根据题干要求，在文中寻找答案所在的语句或段落，进行分析理解，词义猜测，推理判断和概括归纳，选出正确的选项。例如小题2，根据 Instead, the CSF goes into and through the brain along the outsides of the blood vessels (血管), it was actually helping to clear away and clean the waste from the spaces between the brain’s cells (细胞).可知，CSF帮助清理我们大脑里的垃圾，故选B。