单选题 Obesity generally is defined as an accumulation of fat beyond what is considered normal for a person's age, sex, and body type. In today's society obesity is considered a disease, not a moral failing. It occurs when energy intake exceeds the amount of energy expended over time. Only in a small minority of cases is obesity caused by such illnesses as hypothyroidism, or the result of taking medications, such as steroids (类固醇), that can cause weight gain.
The more a person weighs, the more blood vessels the body needs to circulate blood throughout the body. The heart takes on a heavy burden as it has to pump harder to force the blood flow through so many vessels. As a result, the heart grows in size and blood pressure tends to rise. Obesity is also a factor in osteoarthritis (because of the extra weight placed on the joints), bone and joint diseases, respiratory ailments, gallbladder disease, complications during pregnancy and delivery, and higher accidental death rate.
Obesity can alter hormone levels, affect immune function, and cause impotence in men and reproductive problems in women. Women who are 30% overweight are twice as likely to die of endometrial cancer, and those who are 40% overweight have four times the risk. Obese women also are more likely to incur cancers of the breast, ovaries, and gallbladder. Obese men are more likely to develop cancers of the rectum, colon, bladder, pancreas, stomach, and prostate.
Obesity can also cause psychological problems. Sufferers are associated with laziness, failure, or inadequate willpower. As a result, overweight men and women blame themselves for being heavy, thus causing feelings of guilt and depression.
Scientific evidence has found an association between BMI (body-mass index) and higher death rates. However, the relative risk of being heavy declines with age. Some researchers have found that data linking overweight and death are inconclusive, while other researchers have found that losing weight may be riskier than dangers posed by extra pounds. Some researchers counter that overweight indirectly contributes to over 300,000 deaths a year.
A poll by Shape Up America found that 78% of overweight or obese adults have abandoned dieting as a means of losing weight. Diets do not teach people how to eat properly. They merely restrict food intake temporarily, so when the diet ends, weight gain resumes.

单选题 Which of the following expresses the main idea of this passage?

【正确答案】 D

【答案解析】定位：这是一道主旨题，需要在浏览全文的基础上作答。选项A说“肥胖会给心脏增加负担”，虽然这一说法正确，但是太过片面，不足以概括文章主旨，故排除。选项B说“许多人还在不断地节食”，但从文章最后一段来看，大多数人已经放弃了节食这种减肥方法，所以这种说法也不正确。选项C“肥胖被认为是一种疾病”的说法本身正确，但仍不能概括全文。选项D说“肥胖会导致许多严重的健康问题”，从全文来看，第二、三、四段用于陈述“肥胖带来的危害”，该选项与文章主旨最相符，所以本题选D。

单选题 According to the passage, ______.

【正确答案】 C

【答案解析】定位：题干中没有明确的定位信息，只能逐一查看选项。从文章的第一段可以看出，只有为数不多的肥胖是由药物引起的，选项A中使用了often一词，显然是错误的。文章第三段的最后两句分别列举了肥胖的女性和男性在患癌症方面风险增加，这与选项B的观点刚好相反，所以B不正确。文章的第一句话就给肥胖下了一个定义，定义中指出肥胖是指“脂肪堆积超过了一个人的年龄、性别或者体型的正常水平”，由此可知选项C的说法正确，所以本题选C。选项D的内容在文中没有提及，但根据常识，也可以判断出这个说法是错误的。

单选题 According to the passage, why does dieting not result in permanent weight loss?

【正确答案】 A

【答案解析】定位：根据题干中的信息词dieting，可以把答题线索定位到文章的最后一段。文章最后一段指出“节食并不能教会人们合理饮食。节食只不过是在短期内限制食物的摄入，所以当节食结束后，体重增长会再次继续”，选项A的内容与此完全吻合，所以本题选A。选项B中的guilt and depression出现在文章的第四段，是指肥胖引起的心理疾病，与节食无关。选项C和D在文中均未提及。

单选题 Which of the following is implied in Paragraph 5?

【正确答案】 D

【答案解析】定位：根据题干信息，可直接定位到第五段。第五段提到一些研究人员发现“减肥也许要比超重几磅风险更大”，但是并没有专门讲老年人不适合减肥，所以选项A不正确。选项B的内容文中并未提及。选项C说“所有肥胖的人都需要把多余的重量减掉”，这显然与某些研究人员的发现是冲突的，故排除。第五段主要介绍了研究人员对肥胖问题的不同研究结果和看法，说明肥胖问题比较复杂，解决起来并不简单，选项D“胖人应该向医生咨询减肥的利弊”正好印证了文中的观点，所以本题选D。

单选题 Which of the following can be concluded from this passage?

【正确答案】 C

【答案解析】定位：本题也需要在浏览全文的基础上进行作答。选项A说“肥胖不是威胁健康的一个主要因素”，但本文一直在讲肥胖给人带来的各种健康危险，所以A不正确。选项B的内容与文章第五段的内容相悖，所以B错误。选项C说“人们容易对肥胖的人产生偏见”，文中提到肥胖不仅会引起健康疾病，还会导致心理疾病，并且肥胖经常与“懒惰、失败或者意志力不坚定联系在一起”，正好可以得出选项C这个结论，所以本题选C。与选项D对应的内容出现在文章第四段，但是肥胖症患者通常责备的是“自己”，而不是“他人”，所以该选项也不正确。