题目内容：

    A study has found that a lifetime of regular exercise and activity can slow down the aging process (衰老过程). Researchers say that getting older should not necessarily mean becoming more weak or sick. Their research shows that a devotion to a life of movement and exercise may help us live not only longer, but also healthier.

For their study, the researchers looked at two groups. The first group was made up of 125 non-professional cyclists between the ages of 55 to 79. This group included 84 healthy men and 41 healthy women. We will call this group the “cyclists”.

Researchers then found 130 people to make up a second group. Within this group, 75 people were aged from 57 to 80. The other 55 were between the ages of 20 and 36. The people in this group were also healthy, but they did not exercise regularly. We will call this group the “non-exercisers”. Smokers, heavy drinkers of alcohol and people with other health issues were not included in the study.

Then, researchers gave both groups a series of tests. They tested their muscle mass (肌肉质量), muscular strength, percentage of body fat and the strength of their immune (免疫的) systems. Then the researchers compared the results of the two groups.

Results showed that the cyclists did not experience body changes usually regarded as a normal aging process. For example, they did not lose muscle mass or muscular strength. Also, their body fat did not increase with age.

The researchers also found something they had not expected. The study showed that the immune systems of the cyclists did not age either.

The researchers advise us all to find an exercise that we like in our lives.

1.How did the researchers carry out the study?

A. By comparing. B. By discussing.

C. By imagining. D. By reasoning.

2.Which of the following is a result of the research?

A. The cyclists kept a thin body shape.

B. The non-exercisers gained weight easily.

C. The cyclists’ muscles remained strong with age.

D. The non-exercisers usually had health problems.

3.Which is an unexpected result for the researchers?

A. The cyclists had normal aging process.

B. The cyclists’ immune systems didn’t age.

C. The cyclists lost nearly all their fat.

D. Everyone needed an exercise in their lives.

4.Which of the following can be the best title for the text?

A. Healthy People Need More Exercise

B. Take an Exercise, the Harder, the Better

C. Cycling Is the Best Way to Prevent Aging

D. A Lifetime of Exercise Slows Aging Process