Most young people enjoy some form of physical activity. It may be a game of some【B1】______—football, hockey, golf, or tennis. It may be mountaineering. Those who have a(n) 【B2】______for climbing mountains are often【B3】______with astonishment. Why are men and women willing to【B4】______cold and hardship, and to take risks in high mountains This astonishment is caused,【B5】______, by the difference between mountaineering and other forms of activity. Mountaineering is a sport and not a game. There are no man-made rules,【B6】______there are for such games as golf and football. There are, 【B7】______, rules of a different kind which it would be dangerous to【B8】______, but it is this freedom from man-made rules that makes mountaineering【B9】______to many people. Those who climb mountains are【B10】______to use their own methods. If we compare mountaineering and other more【B11】______sports, we might think that one big【B12】______is that mountaineering is not a "team game". We should be mistaken【B13】______this. There are, it is true, no "matches" between "teams" of climbers, but when climbers are on a rock face【B14】______by a rope on which their lives may depend, there is【B15】______teamwork. The mountain climber knows that he may have to【B16】______forces that are stronger and more powerful than man. His sport requires high mental and physical【B17】______. A skier is probably past his【B18】______by the age of thirty, and most international tennis champions are in their early twenties. But it is not【B19】______for men of fifty or sixty to climb the highest mountains in the Alps. They may take more time than younger men, but they probably climb with more skill and less【B20】______of effort, and they certainly experience equal enjoyment. 【B2】

A. passion
B. emotion
C. sense
D. mind