阅读理解。 What would you think if I told you I could eat 40 percent more food than other people eat boxes of ice cream, bowls of noodles and plates of meat -- and all the while be losing weight? You might hate me, thinking 1 have one of those good metabolisms (新陈代谢) that just burn up fat when it enters my body. You might wonder if I have an eating disorder. Or maybe you'd just shrug your shoulders and figure I have a rich fantasy life. You'd be wrong. For my body to perform such a surprising task , I would have to be a mouse. Not just any mouse, but one lucky enough to be involved in a new study at Baylor College of Medicine in Houston. In the study, after discovering an enzyme (酶) that allows fat to be stored in the body, scientists fed mice without those enzymes, and found those mice were able to eat far more food than other mice  and still weighed 10 to 15 percent less. Best of all, the mice without the enzyme were in very good health, were able to produce baby mice without any problem and generally acted like any other mouse. That's great news for researchers, who think that scientists may figure out a way to prevent the fat-metabolizing enzyme in humans as a way to control weight gain. And such a pill would be very exciting for many struggling to get rid of dangerous extra pounds. But don't start planning any big dinner just yet: At this point, of course, any pill for humans is but a twinkle (闪烁) in the eye of every drug company's CEO. More tests are to be conducted, and eventually humans will be tested. But for now, unfortunately, controlling what you eat is still the key to losing weight. 1. What does the underlined part in Paragraph 3 refer to? A. Eating a lot of food while losing weight. B. Burning fat very quickly. C. Controlling your diet. D. Having a rich fantasy life. 2. The study at Baylor College of Medicine ______. A. included both mice and humans B. proved that there is a kind of enzyme which can cause weight gain C. only included mice which didn't have the fat - metabolizing enzyme D. proved that all mice can control their weight easily 3. What does the author want to tell us in the last paragraph? A. You can be free of guilt when having big dinners. B. Scientists can't find the key to discovering the enzyme. C. The best way for people to lose weight now is still to control their diet. D. Drug companies will make a lot of money in the future. 4. It can be inferred from the passage that ______. A. some drug companies have produced pills that help lose weight B. eating a healthy diet is a good way to prevent disease C. the fat -metabolizing enzyme can improve metabolisms D. the pills that help people control weight gain will be very popular if they are available