阅读理解 Imagine eating everything delicious you want - with none of the fat. That would be great, wouldn''t it? New "fake fat" products appeared on store shelves in the United States recently, but not everyone is happy about it. Makers of the products, which contain a compound called olestra, say food manufacturers can now eliminate fat from certain foods. Critics, however, say the new compound can rob the body of essential vitamins and nutrients (营养物) and can also cause unpleasant side effects in some people. So it''s up to consumers to decide whether the new fat-free products taste good enough to keep eating. Chemists discovered olestra in the late 1960s, when they were searching for a fat that could be digested by infants more easily. Instead of finding the desired fat, the researchers created a fat that can''t be digested at all. Normally, special chemicals in the intestines (肠) "grab" molecules of regular fat and break them down so they can be used by the body. A molecule of regular fat is made up of three molecules of substances called fatty acids. The fatty acids are absorbed by the intestines and bring with them the essential vitamins A, D, E, and K. When fat molecules are present in the intestines with any of those vitamins, the vitamins attach to the molecules and are carried into the bloodstream. Olestra, which is made from six to eight molecules of fatty acids, is too large for the intestines to absorb. It just slides through the intestines without being broken down. Manufacturers say it''s that ability to slide unchanged through the intestines that makes olestra so valuable as a fat substitute. It provides consumers with the taste of regular fat without any bad effects on the body. But critics say olestra can prevent vitamins A, D, E, and K from being absorbed. It can also prevent the absorption of carotenoids (类胡萝卜素), compounds that may reduce the risk of cancer, heart disease, etc. Manufacturers are adding vitamins A, D, E, and K as well as carotenoids to their products now. Even so, some nutritionists are still concerned that people might eat unlimited amounts of food made with the fat substitute without worrying about how many calories they are consuming.

单选题 We learn from the passage that olestra is a substance that__________.

【正确答案】 D

【答案解析】细节判断题。正确答案为D，见文章第一段和第二段：“设想一下吃任何你想吃而又不含脂肪的东西吧(Imagine eating everything delicious you want with none of the fat)；这种产品含有一种叫olestra的化合物，其制造商说，现在，食品生产商能把某些食物中的脂肪消除(Makers of the products，which contain a compound called olestra，say food manufacturers can now eliminate fat from certain foods)。可见olestra是一种既能保持美味又不含脂肪的物质。

单选题 The result of the search for an easily digestible fat turned out to be__________.

单选题 Olestra is different from ordinary fats in that__________.

【正确答案】 A

【答案解析】细节判断题。见文章第六段第一句话：Olestra由6—8个脂肪酸分子构成，因其太大而无法被肠道吸收(Olestra，which is made from six to eight molecules of fatty acids，is too large for the intestines to absorb)，而文章第四、五段介绍的是普通脂肪的被正常吸收，可见Olestra与普通脂肪的区别在于“通过肠道但不被吸收”，A为正确答案。