【正确答案】
A
【答案解析】[解析] In recent years, many Americans of both sexes and various ages have become increasingly interested in improving their bodies. They have become more devoted to physical fitness. Many persons have a strong desire to become more physically fit. By nature, Americans are enthusiastic, and energetic about hobbies or pastimes. And now man}' of them apply this enthusiasm, optimism, and energy to running. {{U}}As a result, there are more running clubs to join and numerous books and magazines to read about running.{{/U}}
{{U}}The desire for American people to be physically fit could probably be explained by a "passion" for good{{/U}} {{U}}health.{{/U}} The high rate of heart attacks in the 1960s has caused an increase of interest in improving the health condition of human body. {{U}}Middle-aged men especially suffer from heart attacks.{{/U}} Thus, they are one group strongly interested in taking more physical exercise. {{U}}In fact, many doctors often encourage their patients to become more physically active, especially those who have inactive jobs.{{/U}} It is quite interesting to note that the rate of heart attacks began to decrease between 1972 and 1974 and it is still decreasing now.
It seems that physical fitness has now become a new "love" of Americans. But will it last very long? Nobody knows. Only time will tell—or until another "new passion" comes along and takes its place.
What happens when American people apply great enthusiasm in running?
细节题。文中提到，涌现了越来越多的跑步俱乐部和无数有关跑步的书籍和杂志。关键是as a result这个标志性词组，其意思是“结果是”。