题目内容：

Lack of exercise is considered a risk factor for cancer. There is considerable evidence that inactivity is connected with increased risk for lung cancer, breast cancer, etc.

In the Aerobics Center Longitudinal Study, more than 32,000 people (25,000 men and 7,000 women) were given a preventive medical examination that included a machine exercise test to measure physical fitness. They were given a physical fitness score, with one being the lowest and five being the highest fitness level. Then these people were followed for an average of 8 years. During this time, 179 men and 44 women died of cancer.

Data from the Aerobics Center Longitudinal Study show people have lower rates of cancer with higher levels of physical fitness. Studies from the Cooper Institute for Aerobics Research in Dallas suggest that men with high fitness levels are less likely to die of cancer.

The Aerobics Center Longitudinal Study also found that fitness level was more important than weight in predicting longevity (长寿). While results showed that fitness and normal weight are the ideal combination, researchers found that men who were fat but performed well in the machine performance had just a slightly increased all-cause death rate, including cancer, compared to the more slim men. The fat, but fit, men particularly lived longer than the slim, but flabby (肌肉松弛的), men.

These statistics called for a warning to the overweight: The first health goal for the overweight should be to become as fit as possible at their current weight.

67. 1.The text mainly talks about________.

A．the effect of exercise on reducing chances of cancer

B．how to lose weight effectively

C．different ways to keep slim

D．fat men live longer than slim ones

68. 2.What’s Paragraph 2 mainly about?

A．The study on the life of the overweight.

B．The study on the relationship between taking exercise and cancer.

C．The study on the ways of losing weight.

D．The study on the effects of machine exercise.

69. 3.Which of the following is NOT true according to Paragraph 4?

A．Fitness levels have more effects than weight on people’s longevity.

B．A man who is fit and has normal weight is most likely to live longer.

C．Slim men are more likely to live longer.

D．Fat people who like exercising are also likely to live longer.

70. 4.The author thinks the most important thing for the overweight is to ______.

A．increase their fitness levels                B．choose to eat vegetables

C．be on a diet                            D．ask for help from doctors