2017年考研英语阅读理解考前冲刺试题第五套

来源：华课网校 [2016年12月5日] 【大中小】

　　第1页：2017年考研英语阅读理解考前冲刺试题第五套

　　第2页：考研各科目历年真题汇总（2016-2011）

　　第3页：2017年考研热点资讯推荐

　　第4页：2017考研英语模拟试题

　　第5页：2017考研英语备考辅导

　　You hop into your car， but， wait， where are the keys? You meet someone new， but her name is gone before the handshake's over. Those are failures of your short-term， or “working，” memory——the place you file information for immediate， everyday retrieval. It isn't perfect. But researchers are increasingly convinced that the hormone estrogen could play a key role in maintaining and perhaps even improving memory. Last week a team of Yale scientists provided dramatic new evidence that bolsters the theory. Using MRIs——detailed snapshots of the brain——researchers found that women taking estrogen show significantly more activity in brain areas associated with memory than women on a placebo. “This is very exciting，” says Yale's Dr. Sally Shaywitz. “It means that the brain circuitry for memory had altered.”

　　After menopause， when estrogen levels plummet， some women become forgetful. Past research has demonstrated that those who take estrogen do better on memory tests than their nonmedicated peers do. The hormone may even reduce the risk of Alzheimer's. The new study， published in last week's Journal of the American Medical Association， is the first to visually compare the neurocircuitry of memory both on and off estrogen. The drug made a big difference to participant Bernadette Settelmeyer： “All of a sudden I was remembering things.”

　　The women (whose average age was 51) lay down in a brain-imaging machine where they were shown two types of information： nonsense words (“BAZ” or “DOB”) to test verbal memory and geometric patterns to assess visual memory. After a 20-second “storage” period， participants saw a mix of old and new and were asked if anything looked familiar. During each stage of the test——as the women encoded， stored and retrieved data——researchers took pictures of their brains. The 46 women underwent the test twice——once while taking a standard daily dose of estrogen and again while taking a placebo. Beyond the power of estrogen， the difference in MRIs suggests that the adult brain maintains “plasticity”——the ability to rewire itself——even as it ages.

　　There is still plenty of research to be done. Scientists can't yet be sure estrogen is directly responsible for better memory performance. Despite the difference in brain activity on and off estrogen， participants' scores did not change. Researchers say that is probably because the tasks were so simple (the women got more than 90 percent correct overall)。 Other studies on estrogen and cognition are short term——and their findings have been inconsistent. And scientists still can't answer the question facing millions of women： should I take hormone-replacement therapy? The new study may make estrogen more appealing， but it should be just “one part of the equation，” says Shaywitz. Still， it's a memorable one.

　　注(1)：本文选自Newsweek; 04/19/99， p50;

　　注(2)：本文习题命题模仿对象2002年真题Text 3;

　　1. The following are the examples of the failures of short-term memory， except that ___________.

　　[A]you are not sure whether you‘ve locked the door or not

　　[B]you cannot recall all your previous experience

　　[C]you cannot find the key to your car when starting it

　　[D]you forget the name of a stranger before the greeting is over

　　2. It can be inferred from the text that women‘s working memory could probably be improved if _________.

　　[A]they overuse estrogen

　　[B]they participate in the experiment

　　[C]their minds are kept active

　　[D]the estrogen level is raised