单选题 Passage Three When trying to understand why some people have trouble living within their means, we tend to blame factors such as high interest rates and irresponsible spending. Now researchers have found another possible factor to add to the list: a gene linked to credit-card debt. Earlier work has shown that genetics plays a role in how we handle money. But a recent study was the first to show that a particular gene affects financial behavior outside the lab. Researchers at the University of California, San Diego, and the London School of Economics looked at genetic data and questionnaires already collected from more than 2,000 young adults aged 18 to 26 as part of the National Longitudinal Study of Adolescent Health. In particular, they looked at whether these young adults said they had any credit-card debt and what version of the MAOA gene they had. Monoamine oxidase A (MAOA) (甲型单胺氧化酶) is an enzyme that breaks down the signaling chemicals called neuro-transmitters in the brain. Previous studies have linked the low-efficiency versions of the MAOA gene - the variants that cause less MAOA to be produced by brain cells - to impulsiveness. In the new study, people with one “low” MAOA gene and one “high” MAOA gene reported having credit-card debt 7.8 percent more often than did people with two “high” versions, the researchers found, even when they controlled for factors such as education and socioeconomic status. For people with two “low” versions of the gene, that number jumped to 15.9 percent. The researchers were surprised by the magnitude of the difference. “The effect is almost as big as financial literacy,” meaning people’ s ability to digest complicated financial information, says Jan-Emmanuel de Neve, an author of the study. But, de Neve cautions, an individual’ s version of the MAOA gene does not predict whether he or she is carrying debt. The gene affects credit-card debt the way other genes have been found to play a role in breast cancer: a particular version of the gene increases risk, but many other genetic and environmental factors are important, too. Questions 11-15 are based on Passage Three.
单选题 The recent study has found that __________.
【正确答案】 D
【答案解析】在第二段中我们可以找到相关信息，近期的研究第一次提出实验室未发现的一种特殊的基因影响了我们的财政行为(But a recent...outside the lab)。综合考虑，D项最符合。答案为D。
单选题 What have earlier studies proved?
【正确答案】 A
【答案解析】在第二段开头就指出早期的研究工作显示出基因在我们如何处理金钱问题上发挥着作用(Earlier work has shown…we handle money)，与A项的含义相近。答案为A。
单选题 What does MAOA refer to?
【正确答案】 C
【答案解析】第三段开头就指出MAOA is an enzyme...，由此我们可得出答案。答案为C。
单选题 What can we learn from Paragraph 4?
【正确答案】 B
【答案解析】第四段主要讲了拥有不同MAOA的人的负债情况，文种涉及到了四种关于MAOA的情况：one low，one high，two high和two low，这其实指的是含有MAOA这种酶的变体的情况。所以A和C项单纯比较含有两种不同MAOA变体的人的负债情况是不正确的。D项意为大脑细胞可以产生多少MAOA取决于一个人有多少MAOA的基因，这一点文中并无定论。答案为B。
单选题 According to the last paragraph, what does de Neve want to clarify about their research findings?
【正确答案】 D
【答案解析】de Neve提醒说，个体中含有MAOA基因的种类不能预测出他/她是否负债。这种基因影响信用卡的债务情况的方式就像发现其他的基因对引起乳腺癌发挥的作用一样：有一种很特定的MAOA变体增加了这种危险，但是很多其他的基因和环境因素也很重要(hut many other genetic and environmental factors are important, too)。文章最后强调出了“其他基因”和“环境”对信用卡负债的影响，因此前三项只是列举(MAOA)gene的影响的表述肯定是错误的。答案为D。