2010考研英語閱讀精讀100篇(高分版)TEXT  EIGHT
　　A boy or a girl? That is usually the first question asked when a woman gives birth. Remarkably, the answer varies with where the mother lives. In rich countries the chances of its being a boy are about 5% higher than in poor ones. Equally remarkably, that figure has been falling recently. Several theories have been put forward to explain these observations. Some argue that smoking plays a role, others that diet may be important. Neither of these ideas has been supported by evidence from large studies. But new research points to a different factor: stress.

　　Strange as it might seem, the terrorist attacks of September 11th 2001 shed light on the enigma. Studies noting the sex of babies conceived in New York during the week of the attacks found a drop in the ratio of males to females. That is consistent with earlier studies, which revealed a similar shift in women who became pregnant during floods and earthquakes and in time of war. Moreover, a study carried out eight years ago by researchers at the University of Aarhus, in Denmark, revealed that women who suffered the death of a child or spouse from some catastrophic illness around the time they conceived were much more likely to give birth to girls than to boys.

　　Taken together, these results suggest that acute stress to a woman at the time of conception shifts the sex ratio towards girls. However, Carsten Obel, a researcher at Aarhus who was not involved in the earlier study, wondered if the same might be true of chronic stress too. In a paper just published in Human Development, he shows that it is.

　　Dr Obel used a set of data collected between 1989 and 1992. During that period 8,719 expectant mothers were asked to fill in questionnaires that inquired, among other things, about their level of stress. Dr Obel found that the more stressed a mother had been, the less chance she had of having given birth to a boy. Only 47% of children born to women in the top quartile of stress were males. That compared with 52% for women in the bottom quartile. Dr Obel suspects the immediate cause is that male pregnancies are more likely to miscarry in response to stress than female pregnancies are, especially during the first three months. However, that is difficult to prove. More intriguing, though, is the ultimate cause, for he thinks it might be adaptive, rather than pathological.

　　That is because the chances are that a daughter who reaches adulthood will find a mate and thus produce grandchildren. A son is a different matter. Healthy, strapping sons are likely to produce lots of grandchildren, by several women—or would have done in the hunter-gatherer societies in which most human evolution took place. Weak ones would be marginalised and maybe even killed in the cut and thrust of male competition. If a mother's stress adversely affects the development of her fetus then selectively aborting boys, rather than wasting time and resources on bringing them to term, would make evolutionary sense.

　　That, in turn, would explain why women in rich countries, who are less likely to suffer from hunger and disease, are more likely to give birth to sons. That this likelihood is, nevertheless, falling suggests that rich women's lives may be more stressful than they used to be.

　　1. The author begins the passage by_____

　　[A] presenting an argumentation.

　　[B] explaining a phenomenon.

　　[C] raising a question.

　　[D] making a comparison

　　2. The ratio of giving birth to a boy is falling in rich countries because_____

　　[A] the terrorist attacks of September 11th 2001 exerted huge negative impact.

　　[B] women are facing greater pressure than past.

　　[C] women are under new pressure now which they seldom faced in the past.

　　[D] male pregnancies are more easily to miscarry.

　　3. Which of the following can explain Dr Obel’s opinion that the ultimat cause is adaptive rather than pathological?

　　[A] 47% of children born to women in the top quartile of stress were males while 52% in the bottom quartile.

　　[B] Women in rich countries are more likely to give birth to boys.

　　[C] Women selectively abort boys rather than waste time and resources on bringing them to term for fear of male competition.

　　[D] Women who suffer from calamity in conception are more likely to give birth to girls.

　　4. Women in the hunter-gatherer societies are more likely to give birth to daughters because_____

　　[A] they agree that giving birth to daughters is beneficial in the evolutionary sense.

　　[B] sons are likely to produce lots of grandchildren with several women.

　　[C] they think it is a better practice for a daughter to produce grandchildren with only one mate.

　　[D] they think bringing sons to term is wasting time and resources.

　　5.From this passage, we may draw a conclusion that_____

　　[A] acute stress is more likely to cause women to choose aborting boys than chronic stress.

　　[B] stress to a woman at the time of conception, whether acute or chronic, will shift the sex ratio towards girls.

　　[C] more girls will be born in the future because today’s women, in both rich and poor countries, suffer from increasing pressure.

　　[D] chronic stress is more decisive in influencing the women’s pregnancies.

　　文章剖析：

　　這篇文章是介紹影響嬰兒出生性別原因的一個新的研究成果--壓力。文章第一段提出以往人們對該問題的看法，然后引出新的研究結(jié)果;第二段用一些事例來證明突發(fā)壓力對于嬰兒性別的影響;第三段、第四段講述Obel博士調(diào)查研究表明慢性壓力在這方面的影響;第五段對Obel博士的研究結(jié)果作了一些論證;第六段是對第一段提到的現(xiàn)象用得出的結(jié)論做解釋。

　　詞匯注釋：

　　enigma n. 謎

　　conception n. 受精

　　chronic adj. 長期的，持續(xù)的

　　questionnarie n. 調(diào)查表

　　quartile n. 四分位值

　　miscarry v. 流產(chǎn)

　　pathological adj. 病理的

　　strapping adj. 偉岸的，魁梧的

　　fetus n. 胎兒

　　難句突破：

　　(1) Moreover, a study carried out eight years ago by researchers at the University of Aarhus, in Denmark, revealed that women who suffered the death of a child or spouse from some catastrophic illness around the time they conceived were much more likely to give birth to girls than to boys.

　　[主體句式] A study revealed that…

　　[結(jié)構(gòu)分析]這是一個復(fù)合句，主語后面是一個過去分詞短語做定語;revealed后面的賓語從句比較復(fù)雜，從句的主體句式為women or spouse were likely to …，狀語中that 引導(dǎo)的定語從句用來修飾time, 第一個主語women后有一個以who引導(dǎo)的定語從句。

　　[句子譯文] 而且，八年前奧爾胡斯大學(xué)研究者們做的一項研究也表明，經(jīng)過頭胎死亡經(jīng)歷或配偶在其懷孕期間患上一些災(zāi)難性疾病的婦女更有可能生女孩。

　　(2) If a mother's stress adversely affects the development of her fetus then selectively aborting boys, rather than wasting time and resources on bringing them to term, would make evolutionary sense.

　　[主體句式] If… then selectively aborting boys…would make sense.

　　[結(jié)構(gòu)分析] 這是一個帶有條件狀語從句的復(fù)合句，主語由現(xiàn)在分詞短語構(gòu)成。

　　[句子譯文] 如果母親受到的壓力對胎兒發(fā)展起到相反作用，選擇性地將男孩流產(chǎn)，而不是浪費時間和資源將他們養(yǎng)大，這從進化意義上說得通的。

　　題目分析:

　　[答案]A

　　[難度系數(shù)] ☆

　　[分析]推理題。作者在文章一開始就指出在富裕國家中婦女生男孩的比率比貧窮國家高出5%，但目前這個比率在下降，有許多人給出自己的解釋，但都不能被大型的研究所證明，而現(xiàn)在又有新的論點，就是壓力的作用。接下來的幾段就是對這個論點的證實�？梢姡�作者是以提出一個論點的形式來開始這篇文章的。

　　[答案]B

　　[難度系數(shù)] ☆☆☆

　　[分析]推理題。首先A選項明顯是錯誤的，因為這個影響只限于美國，并不包括所有的富裕國家。D也是錯誤選項，因為文章第四段中提到了這一點，但是選項中卻丟掉了一個重要前提，也就是在較大的壓力下，懷了男孩的女性才更加容易流產(chǎn)。題干要求找出富裕國家目前男孩出生率下降的原因，文章整篇都在討論壓力對于嬰兒性別的作用，而比較后一段的比較后一句話作者指出，目前這個比率下降可能是因為富裕國家婦女現(xiàn)在承受的壓力要比以前多，但是沒有說明有新的壓力。因此，答案為B。

　　[答案]C

　　[難度系數(shù)] ☆☆☆

　　[分析]細節(jié)題。第四段中提到，Obel博士認為導(dǎo)致女性在面臨壓力時生女孩的幾率更大，其根本原因應(yīng)該是適應(yīng)性的原因而不是生理性原因。第四段提到，Obel懷疑是其直接原因是面臨壓力時如果懷孕的是男孩那么就更容易流產(chǎn)。緊接著第五段就給出了解釋，那就是在資源緊缺的男性競爭社會中，弱小的男性更容易被邊緣化，被淘汰，而女性則不存在這個問題，所以面對這種壓力，婦女生育孩子時會選擇將男嬰流產(chǎn)，這是一種適應(yīng)環(huán)境的做法。因此，答案中C是可以說明他的這個觀點的，A、B、D只是一些表象。

　　[答案]D

　　[難度系數(shù)] ☆☆☆

　　[分析]推理題。文章第五段指出在原始狩獵社會中，健康、強壯的男性可以和幾位女性一起繁殖許多后代，而弱小的則會被邊緣化甚至在男性競爭中被殺死。婦女在生育孩子時就會面臨這樣的壓力，她更情愿將男嬰流產(chǎn)，也不愿意花費了如此多的時間和精力后將男嬰生出來，卻面臨被淘汰的壓力。因此，在原始狩獵社會中，女孩出生率較高的原因是因為婦女生育時面臨的這種壓力。選項中，D為正確答案。A選項顯然是錯誤的，原始人不會以進化的觀點去思考問題。B選項的說法只是一個現(xiàn)象，并不是題干的原因。C選項的說法與原文相反。

　　[答案]B

　　[難度系數(shù)] ☆☆☆

　　[分析] 推理題。題干要求根據(jù)整篇文章推導(dǎo)出一個結(jié)論，本文主要講述了壓力對于嬰兒出生性別的影響，分別用一些數(shù)據(jù)和事實證明突發(fā)壓力和慢性壓力都有一定的影響，從中可以得出結(jié)論，就是突發(fā)與急性壓力都會使得女孩出生率高一些。答案A、D文中并沒有進行比較、缺少證據(jù)，C的內(nèi)容也文中也沒有提到。因此，正確答案為B。

　　參考譯文：

　　男孩還是女孩?這通常是一個女人生完孩子后問的第一個問題。很顯然的，因為這位母親所在的地方不同答案也就不同。在富裕國家中生男孩的比率要比貧窮國家高5%。同樣引人注目的是，比較近這個數(shù)字有所降低。人們提出了幾個理論來解釋這些現(xiàn)象。有人認為吸煙可能是原因所在，也有人認為節(jié)食的影響較大。但大規(guī)模研究的證據(jù)卻都不支持這兩個觀點，而新的研究指出了另外一個因素：壓力。

　　雖然看起來很奇怪，但2001年“9·11”恐怖襲擊揭示了這個問題的謎底。對恐怖襲擊的那一周在紐約出生嬰兒的性別研究發(fā)現(xiàn)男女性別比例下降了，這與早期的研究一致。早期研究表明洪水、地震和戰(zhàn)爭期間懷孕婦女生育男女的比例也有相似的變化。而且，八年前奧爾胡斯大學(xué)研究者們做的一項研究也表明，經(jīng)過頭胎死亡經(jīng)歷或配偶在其懷孕期間患上一些災(zāi)難性疾病的婦女更有可能生女孩。

　　綜合這些研究結(jié)果表明女性在受精時如果受到突然的壓力，那么生女孩的比例就會增大。但是，奧爾胡斯的一位研究者CarstenObel并沒有參與早期的研究，他懷疑持續(xù)的壓力是否也會有同樣的影響。他剛剛在《人類發(fā)展》上發(fā)表的一篇論文表明事實確實如此。

　　Obel博士使用了1989年至1992年間的一組數(shù)字。在這個時期，8791名婦女受邀填寫問卷調(diào)查，調(diào)查其中一項就是她們壓力程度。Obel博士發(fā)現(xiàn)一個婦女承受的壓力越重，她生男孩的概率就越小。壓力比較大的四成婦女只有47%生育男孩，而比較小的四成婦女比例為52%。Obel博士懷疑這種現(xiàn)象的直接原因是在壓力的情況下，懷男嬰的婦女比懷女嬰的婦女更容易流產(chǎn)，尤其是在前三個月。這一點很難證實。更讓人迷惑的是他認為根本原因是適應(yīng)性的而不是生理性的。

　　這是因為可能的情況是女孩成年后就要找一位男性，然后生育后代。而男孩則不一樣。健康、魁梧的男性更有可能與幾位女性生育很多后代，至少在原始狩獵族社會是這樣的，大多數(shù)人類進化就是這樣進行的。弱小的將會被邊緣化，甚至有可能在男性的競爭性打斗中被殺死。如果母親受到的壓力對胎兒發(fā)展起到相反作用，選擇性地將男孩流產(chǎn)，而不是浪費時間和資源將他們養(yǎng)大，這從進化意義上說得通的。

　　這反過來也可以解釋為什么在富裕國家中女性很少受到饑餓和疾病的威脅，更容易生育男孩。盡管存在這種可能，但是數(shù)據(jù)的下降說明富裕女性目前所受的壓力要比以前大得多。