阅读理解。 Most young people enjoy some form of physical activity.It may be walking, cycling, swimming, or in winter, skating or skiing. It may be a game of some form-football, basketball,hockey, golf or tennis. It may be mountaineering. Those who have a passion ( strong emotion) for climbing high mountains are often looked upon with astonishment. Why are men and women willing to suffer cold and hardship,and to take risks in high mountains? This astonishment is caused, probably, by the differences between mountaineering and other forms of activities. Mountaineering is a sport and not a game. There are no man- made  rules as others ,such as golf and football. There are ,of course , rules of different kinds which it would be dangerous to ignore,but it is this freedom from man-made rules that makes mountaineering at- tractive to many people. Those who climb mountains are free to use their own methods. If we compare mountaineering with other more familiar sports, we might think that one big difference is that mountaineering is not a' team  game ' . There  are ,it  is  true , no ' matches ' between ' teams' of climbers,but when climbers are on a rock linked by a rope on which their lives may depend,there is obviously teamwork. A mountain climber knows that he may have to fight forces that are stronger and more powerful than man. He has to fight the forces of nature. His sport requires high mental and physical qualities. A mountain climber continues to improve in skill year after year. A skier is probably past it by the age of thirty,but it is not unusual for men of fifty or sixty to climb the highest mountain in the Alps. They may take more time than younger men,but they perhaps climb with more skills and less waste of effort,and they certainly experience equal enjoyment. 1. What movements are popular among people in winter in the passage? A. Soccer and golf. B. Skiing and skating. C. Cycling and hockey. D. Mountaineering. 2. Mountaineering is a sport,not a game,because _____  . A. it has man-made rules B. it is too dangerous for climbers C. it can't bring people joy and leisure D. it is free for climbers to use their own methods 3. According to the passage, which of the following statements is TRUE? A. Mountaineering is a match between climbers. B. Mountaineering is similar to other sports in many ways. C. Climbers work like a team when their lives may depend on a rope. D. Climbers help each other in time of difficulty. 4. It can be inferred from the passage that____. A. mountaineering has no appeal to people B. physical quality is more important than mental quality for climbers C. a mountain climber would pass it by the age of thirty D. it is possible for an old man of fifty or sixty to climb the Alps