Question

【題目】 Why would human beings waste a third of their lives sleeping when they could be doing more important things like looking after their families or working? Some scientists believe sleeping helps recharge the body, while others think it is important for strengthening newly-formed memories. Now, there is new evidence which suggests that the purpose of sleep may be to forget some of the millions of new things we learn each day.

The neurons (神經(jīng)元) in the human brain consist of fibers called dendrites (樹突). These grow as we learn new things and connect the brain's cells to each other at contact points called synapses (突觸). The larger the dendrites become and the more cells they connect, the more information we store.

In 2003, Giulio Tononi and Chiara Cirelli, both biologists at the University of Wisconsin-Madison, suggested a new idea: The things our brains learn each day result in so many synapses that things start to get a little messy. Sleeping allows us to sort through the "noise" and dispense all the unnecessary information, leaving behind only the most important memories-

Recently, the university's research has provided direct evidence to support the theory. The experiment involved analyzing 6,920 synapses in the brain shavings from two groups of mice over a four — year period; one group had been allowed to sleep, while the other had been kept awake and entertained with toys. The researchers discovered that the brain shavings of the sleeping mice had nearly 20 percent fewer synapses than those that had been kept awake and entertained.

It was also evident during the study that the brain does not shave every synapse. 20% of neurons remained unchanged; these were most likely well-established memories. Therefore, although we may be sleeping to forget some of what we've learned, the brain "forgets" in a smart way.

Most researchers believe clearing our brains is not the only purpose of sleep. Resting our minds and bodies has also been found to help with other biological functions like strengthening our immunity. Though scientists may never agree on a single reason, they are all sure of one thing — a good night's rest is essential for our health. So try and spend at least a third of your day sleeping!

【1】What will happen when we learn new things?

A.We tend to forget some key information.

B.We develop the ability to recharge the body.

C.The dendrites expand and connect brain's cells.

D.The neurons gather at what are called contact points.

【2】Which of the following can replace the underlined word “dispense” in Paragraph 3?

A.Pick up.B.Get rid of.

C.Bring down.D.Pull out of.

【3】What is the author's purpose of writing the text?

A.To prove a new theory.

B.To report a new discovery.

C.To show sleep good for memory.

D.To discuss how long one should sleep.

Answer 1

【答案】

【1】C

【2】B

【3】B

【解析】

本文為一篇說明文。文章介紹了睡眠的新研究：睡眠的目的可能是忘記我們每天學(xué)習(xí)的數(shù)百萬新事物中的一些。

【1】細節(jié)理解題。根據(jù)第二段These grow as we learn new things and connect the brain's cells to each other at contact points called synapses (突觸).可知，當(dāng)我們學(xué)習(xí)新事物時，這些神經(jīng)元就會生長，并通過叫做突觸的接觸點將大腦細胞相互連接起來。由此可知，當(dāng)我們學(xué)習(xí)新事物時，樹突會擴張并連接大腦細胞。故選C項。

【2】詞義猜測題。根據(jù)后文leaving behind only the most important memories.(只留下最重要的信息)推測前文dispense意為“丟棄”，dispense all the unnecessary information意為“丟棄了不必要的信息”，B項“扔掉”與dispense意思相近。 故選B項。

【3】推理判斷題。結(jié)合全文及第一段Now, there is new evidence which suggests that the purpose of sleep may be to forget some of the millions of new things we learn each day.可知，文章介紹了睡眠的新研究：睡眠的目的可能是忘記我們每天學(xué)習(xí)的數(shù)百萬新事物中的一些。由此推測，作者寫這篇文章是為了報告一個有關(guān)睡眠的新發(fā)現(xiàn)。故選B項。

細節(jié)理解題主要考查考生對文章中某一些特定細節(jié)或文章的重要實事的理解能力。它一般包括直接理解題和語義理解題兩種。直接理解題的答案與原文直接掛鉤，從閱讀材料中可以找到。以本文第1小題為例，本題運用定位法：根據(jù)第二段These grow as we learn new things and connect the brain's cells to each other at contact points called synapses (突觸).可知，當(dāng)我們學(xué)習(xí)新事物時，這些神經(jīng)元就會生長，并通過叫做突觸的接觸點將大腦細胞相互連接起來。由此可知，當(dāng)我們學(xué)習(xí)新事物時，樹突會擴張并連接大腦細胞。故選C項。