结构推理 Directions: In this part there is a short passage with five questions or incomplete statements. Read the passage carefully. Then answer the questions or complete the statements in the fewest possible words (not exceeding 10 words). People who exercise and then reach for more snacks might not lose weight, but they will alter their body chemistry in a way that burns up more fat, a researcher reported. A carefully controlled study showed that fat burning increases significantly with exercise, even if people eat too much. People get their energy by burning a combination of fat and carbohydrates. Those who are naturally lean, burn fat quicker than people who are overweight. Scientists found that exercise shifts the ratio, so people get a higher percentage of their energy from burning fat. The study supports the idea that exercising can help people lose weight. That might seem obvious, but it has even become the subject of debate among obesity (肥胖症) specialists. There’s no question about the cardiovascular (心脏血管的) benefits, and no question exercise is helpful for people with diabetes (糖尿病). But for treatment of obesity, there is a debate. This study involved 20 people. Some were overfed 1,000 calories per day and were not allowed to exercise, while others were overfed and assigned to do just enough exercise to burn up the extra 1,000 calories. In those who were overfed without exercise, the amount of fat burned dropped from the equivalent of 518 calories per day to 97 calories per day. The burning of carbohydrates rose. The researcher acknowledged that the numbers of people in his study were small, but said it is difficult to do large studies when people must be kept in a clinic for days at a time to monitor their diets and their physical activity. The studies so far have been done on people with normal weights, he said. He is now planning similar studies with obese subjects, to see if they react differently to exercise. 1.How does exercise change the way for people to get energy? 2.Why are some people naturally lean while others are overweight? 3.Scientists are in agreement that exercise is helpful for people with 4.How does exercise benefit those who eat more after exercise? 5.Why is the result of this study not very reliable?