【正确答案】 C

【答案解析】[听力原文] W: Mike, why are so many Americans overweight? M: Well, that's a good question, Lily. You'd think that with the current fitness craze in the US, there wouldn't be so many overweight Americans. W: Yes. How many people are overweight? M: About 40% of Americans are overweight. What's interesting is that one study says that lower income groups have a higher percentage of being overweight than higher income groups. W: Are there any other factors like that in the study? M: Yes. The study also says that the hotter the climate is, the lower the percentage of fat people is. W: That makes sense. When it's hot, you usually don't feel like eating a lot. M: Is that why Japanese people are typically skinnier than Americans? W: Well, our food has less fat and oil than American food does. And Americans eat a lot more meat than we do. M: You're right. And we also eat more sugar and junk food. But there's another reason why so many Americans are fat. W: What's that? M: Nobody works out any more—not even kids. The average American home has the TV on for six hours a day! W: Wow! No wonder you Americans are so fat. You don't get enough exercise. Say, Mike, aren't you getting a little bigger in the waist? M: Yeah, I guess so. W: To lose weight, you really need to watch what you eat and get some exercise. M: Hey, I started a diet and lost ten pounds. W: So what happened afterwards? M: I quit and gained it all back plus five pounds. What does the study say about lower income groups?