In the United States, 30 percent of the adult (成年人) population has a “weight problem”. To many people, the cause is clear: we eat too much. But scientific evidence (证据) does little to support this idea. Going back to the America of 1910, we find that people were thinner than today. Yet they ate more food. In those days, people worked harder physically, walked more, used machines much less, and didn’t watch TV.

Several modern studies, moreover, have shown that fatter people do not eat more on average (平均地) than thinner people. In fact, some investigations (调查), such as a 1979 study of 3545 London office workers, reports that fat people eat less than slimmer people.

Studies show that slim people are more active than fat people. A study by a research group at Standford University School of Medicine found the following interesting facts:

The more the men ran, the more fat they lost.

The more they ran, the more they ate.

Thus, those who ran the most ate the most, yet lost the greatest amount of body fat.

1.What kind of physical problem do many adult Americans have?

A They are too thin.

B They work too hard.

C They are too fat.

D They lose too much body fat.

解析：选C。C 细节理解题。根据第一段第一句可知，百分之三十的美国成年人有“体重问题”。故选C。

2.According to the information given in the passage, among 500 Americans, how many have weight problem?

A 30

B 50

C 100

D 150

解析：选D。D 细节理解题。根据第一段第一句可知，百分之三十的美国成年人有“体重问题”，因此500人中有(500*30%=)150人有“体重问题”。故选D。

3.Which of the following words can take the place of the word “slim” in this passage?

A poor

B thin

C healthy

D rich

解析：选B。B 词义猜测题。根据第二段最后一句及第三段第一句可知，slim是fat的反义词。故选B。

4.Compared with (与……相比) the adult American population today, the Americans of 1910 ________.

A ate more food and had more physical activities

B ate less food but had more activities

C ate less and had less physical exercise

D had more weight problems

解析：选A。A 细节理解题。根据第一段后半部分呢可知，1910年的美国人吃得更多，身体活动得更多。故选A。

5.What have modern medical and scientific researches reported to us?

A Fat people eat less food and are less active.

B Fat people eat more food than slim people but are less active.

C Fat people eat more food than slim people but are more active.

D Thin people run less, but have greater increase in food intake.

解析：选A。A 细节理解题。根据第二段和第三段可知，胖的人吃得更少、活动更少。故选A。