题目内容：

“Preventing obesity (肥胖) and smoking can save lives, but it doesn’t save money,” reported researchers. “It was a small surprise, for it is against the common belief,” said Pieter van Baal, who led the study. “But it makes sense. If you live longer, then your costs of the health system will be more.”

The researchers found that from age 20 to 56, obese people racked up (累计) the most expensive health costs. But on average, healthy people lived 84 years. Smokers lived about 77 years, and obese people lived about 80 years. Smokers and obese people tended to have more heart disease than healthy people. Therefore in the long run, the thin and healthy group spent about $ 417,000, from age 20 on. Smokers spent about $ 326,000 and obese people $ 371,000.

“The result throws a bucket of cold water onto the idea, based on guesswork, that obesity is going to cost trillions of dollars,” said Patrick Basham, a professor of health politics. “If we’re going to worry about the future of obesity, we should stop worrying about its financial impact,” he said.

“The benefits of obesity prevention may not be seen immediately in terms of cost saving in tomorrow’s budget, but there are long-term gains,” said Baal. “These are often immeasurable when it comes to people living longer and healthier lives.” In the meanwhile, he said that governments should recognize that successful smoking and obesity prevention programs mean that people will have a higher chance of dying of something more expensive later in life.

“Lung cancer is a cheap disease to treat because people don’t survive very long. But if they are old enough to get Alzheimer’s (早老性痴呆病) one day, they may survive longer and cost more. We are not advising that governments stop trying to prevent obesity,” Baal said. “But they should do it for the right reasons.”

1.Among middle-aged people, whose costs of the health system are the most?

A. Those who are heavy smokers.

B. Those who are overweight.

C. Those who are too thin.

D. Those who are suffering from heart attacks.

2.What can we know about the belief that obesity costs much?

A. It turns out to be incorrect.

B. It comes from scientific studies.

C. It is based on medical evidence.

D. It has changed over the past years.

3.According to the text, governments should prevent obesity for the purpose of       .

A. reducing the risk of suffering cancer

B. weakening obesity’s financial impact

C. making sure of people’s long and healthy life

D. reducing the money spent on medical programs

4.What would be the best title for this text?

A. A Recent Medical Study Shows the Truth about Health

B. Preventing Obesity and Smoking May Cost More

C. Obesity and Smoking Lead to Expensive Diseases

D. Governments Change Attitude towards Obesity and Smoking