阅读理解 Directions: In this part, there are six passages, each of which is followed by five questions. For each question, there are four possible answers marked A, B, C, and D. Choose the best answer and mark the letter of your choice on the ANSWER SHEET.

Passage Three

Having too much caffeine during pregnancy may impair baby' liver development and increase the risk of liver disease in adulthood, according to a study published in the Journal of Endocrinology. Pregnant rats given caffeine had offspring with lower birth weights, altered growth and stress hormone levels and impaired liver development. The study findings indicate that consumption of caffeine equivalent to 2-3 cups of coffee may alter stress and growth hormone levels in a manner that can impair growth and development, and increase the risk of liver disease in adulthood.

Previous studies have indicated that prenatal caffeine intake of 300 mg/day or more in women, which is approximately 2 to 3cups coffee per day, can result in lower birth weights of their children. Animal studies have further suggested that prenatal caffeine consumption may have more detrimental long-term effects on liver development with an increased susceptibility to non-alcoholic fatty liver disease, a debilitating condition normally associated with obesity and diabetes. However, the underlying link between prenatal caffeine exposure and impaired liver development remains poorly understood. A better understanding of how caffeine mediates these effects could help prevent these health issues in people in the future.

In this study, Prof Hui Wang and colleagues at Wuhan University in China, investigated the effects of low (equivalent to 2-3 cups of coffee) and high doses (equivalent of 6-9 cups of coffee) caffeine, given to pregnant rats,on liver function and hormone levels of their offspring. Offspring exposed to prenatal caffeine had lower level of the liver hormone, insulin like growth factor(IGF-1), and higher levels of the stress hormone, corticosteroid at birth. However, liver development after birth showed a compensatory 'catch up' phase, characterized by increased levels of IGF-1,which is important for growth.

Dr. Yinxian Wen, study co-author, says,"Our results indicate that prenatal caffeine causes an excess of stress hormone activity in the mother, which inhibits IGF-1 activity for liver development before birth. However, compensatory mechanisms do occur after birth to accelerate growth and restore normal liver function, as IGF-1 activity increases and stress hormone signalling decreases.The increased risk of fatty liver disease caused by prenatal caffeine exposure is most likely a consequence of this enhanced, compensatory postnatal IGF-1 activity."

These findings not only confirm that prenatal caffeine exposure leads to lower birth weight and impaired liver development before birth but also expand our current understanding of the hormonal changes underlying these changes and suggest the potential mechanism for increased risk of liver disease in the future. However, these animal findings need to be confirmed in humans.

Dr. Wen comments,"Our work suggests that prenatal caffeine is not good for babies and although these findings still need to be confirmed in people, I would recommend that women avoid caffeine during pregnancy."

单选题 Which of the following is NOT the problem of baby rats of pregnant rats given caffeine?

【正确答案】 B

【答案解析】

全文翻译：

内分泌杂志刊登的一篇研究报告，说孕期如果摄入过多的咖啡因可能会影响婴儿的干的发育，同时也会提高成年后患肝病的风险。摄入咖啡因的怀孕老鼠生下的幼子体重偏低，发育迟缓，应激激素水平较低，并且肝发育受损。这项研究表明每天摄入2-3倍咖啡中所含的咖啡因量可能会改变激素和成长激素的水平，从而伤害肝的发育，并且增加成年后得肝病的风险。

早先的研究已经指出孕妇每天摄入300mg/天以上的咖啡因，也及时相当于每天喝2-3杯咖啡，会导致新生儿出生时体重偏低了动物试验进一步指出孕期过多的摄入咖啡因可能会对肝发育产生长期的不利影响，同时增加非酒精脂肪肝的发病率。这种病一般被认为与肥胖和糖尿病有关。然而，孕妇摄入咖啡因和受损的肝发育的潜在关系还未被大多数人了解。更好滴理解咖啡因是如何造成这样的影响可以帮助人们在未来预防这些健康问题。

来自武汉大学的王辉教授和她的同事们在研究中调查了怀孕母鼠摄入低剂量（2-3杯）和高剂量（6-9杯）咖啡因对幼子的肝功能和激素水平的影响。受到孕期咖啡因的影响，幼子出生时肝部激素、胰岛素样生长因子较低，而应激激素和皮质类固醇水平较高。然而，出生后，肝的发育会有一段补偿性的追赶时期，表现在对生长及其重要的IGF-1的水平快速增长。

文章的共同署名人文博士说：我们的研究结果表明孕期摄入的咖啡因会在母体中引起过度的应激激素活动，这将抑制孩子出生前肝的发育。然而，身体的补偿机制在出生后随着IGF-1的活跃和应激激素指数的降低，加速肝的发育并恢复到肝功能的正常水平。母体咖啡因暴露引起的脂肪肝的风险上升很可能是这种出生后的增强型补偿性IGF-1活动引起的。

这些发现不仅证实了孕期咖啡因接触会导致新生儿体重偏低和产前肝发育受损，而且拓宽了我们对这些动物实验的结果还需要在人体中得到证实。

文博士说：虽然我们的发现还需要人体的证实，但我们认为孕期咖啡因对孕妇和婴儿都有没有好处，因此我建议女性在怀孕期间要避免摄入咖啡因。

细节题。题目问的是“下列哪项不是摄入咖啡因母鼠产下的幼仔遇到的问题？”回归原文： "Having too much caffeine during pregnancy may impair baby's liver development and increase the risk of liver disease in adulthood, according to a study published in the Journal of Endocrinology. Pregnant rats given caffeine had， offspring with lower birth weights, altered growth and stress hormone levels and impaired .liver development. ”，即“内分泌学杂志刊登的一篇研究声称，孕期如果摄入过多的咖啡因可能会影响婴儿的肝的发育，同时也会提高孩子成年后患肝病的风险。摄入咖啡因的怀孕母鼠生下的幼仔体重偏低，发育迟缓，应激激素水平较低，并且肝发育受损。”，分别对应A,C和D项，只有B未提到，故选B。

单选题 If a pregnant woman takes 3 cups of coffee, what will probably happen?

【正确答案】 D

【答案解析】细节题。题目问的是“如果孕妇喝了3杯咖啡，那可能会发生什么?”回归原文： "Previous studies have indicated that prenatal caffeine intake of 300 mg/day or more in women, which is approximately 2 to 3 cups coffee per day, can result in lower birth weights oftheir children” , 即“早先的研究已经指出孕觉每天摄入300毫克以上的咖啡因,也就是相当于每天喝2-3杯咖啡，会导致新生儿出生时体重偏低”，所以第一个影响是体重偏低。而A选项说的是孕妇体重越来越轻,B选项说的是婴儿体重越来越轻，原文并没有提到体重降低的问题，故可排除这两个选项。接下来又提到“Animal studies have further suggested that prenatal caffeine consumption may have more detrimental long-term effects on liver development with an increased susceptibility to non-alcoholic fatty liver disease, a debilitating condition normally associated with obesity and diabetes. ”即"动物实验进一步指出孕期过多摄入咖啡因可能对肝发育产生长期不利的影响，同时增加非酒精性脂肪肝的发病率。这种病一般被认为与肥胖和糖尿病有关”。因此还会影响婴儿肝的发育，增加非酒精性脂肪肝的发病率,进而可能会变得肥胖或得糖尿病。C项“母亲将长期受非酒精性脂肪肝的折磨”，文中没有提及，可排除。D项“由于的问题，孩子更容易发胖或得糖尿病”，与文意相符，故选D。

单选题 Which of following is not correct according to the passage?

【正确答案】 A

【答案解析】综合判断题。题目问的是“根据文章,下列哪项不正确？ ”回归原文：第二段“However, the underlying link between prenatal caffeine exposure and impaired liver develop- ment remains poorly understood.” 提到孕期摄人咖啡因和受损肝发育的潜在关系还未被大多数人了解，由此可知,A与之异•盾;根据第三段“low (equivalent to 2-3 cups ofcoffee) and high doses ( equivalent of6-9 cups ofcoffee) caffeine" 可知，中间值4-5杯篇于中剂量,B选项H确;第四段"compensatory mechanisms do occur after birth to accelerate growth and restore normal liver function" 可知身体的补偿机制在岀生后随着IGF-1活动的活跃和应激激素指数的降低，加速肝的发育并恢复到肝功能的正常水平,C选项正确；文中一直讨论的都是在老鼠身上进行的实验，同时倒数第二段提到“these animal findings need tobe confirmed in humans. ”这些动物实验的结果还需要在人体中得到证实，可知这些实验还没在人体上进行,D选项正确。综上所述，只有A选项不正确，故选A。

单选题 What is the relationship between stress hormone and liver development when taking inprenatal caffeine?

【正确答案】 B

【答案解析】细节题.题目问的是“孕期摄入咖啡因的时候，应激激素和肝发育的关系是忿样的？”回归原文：第三段提到“Offspring exposed to prenatal caffeine had lower levels of the liver hormone, insulin like growth factor (IGF-1) , and higher levels of the stress hormone, corticosteroid at birth.”即“受到孕期咖啡因的影响，幼仔出生时肝部激素、胰岛素样生长因子(IGF-1)较低，而应激激素和皮质类固醇水辛较高。”A项“出生前应激激素和体重都偏低”，B项“出生前应激激素偏高，生长激素偏低”，C项“岀生后应激激素偏高，体重加速增长”，D项"岀生后应激激素偏低，肝部生长速度偏慢”。根据第三段信息，正确答案应该是“出生前应激激素偏高，体重偏低；出生后应激激素降低，肝部生长速度加快”，结合四个选项，故B正确。