[单项选择]Those who have a strong love for climbing high and difficult mountains are often looked upon with astonishment. Why are men and women 16 to suffer cold and hardship, and to 17 on high mountains This astonishment is caused, probably, by the difference between mountaineering and other forms of activity 18 men give their leisure. Mountaineering is a sport and not a game. There are no man-made rules, as there are for such games as golf and football. There are rules of a different kind which it would be dangerous to 19 , but it is this freedom from man-made rules 20 makes mountaineering interesting to many people. Those who climb mountains are free to use their own methods. If we compare mountaineering with other more 21 sports, we might think that one big difference is that mountaineering is not a “team game”. We should not be 22 in this. There are, 23 , no “matches” between “teams” of climbers, but when climbers
A. forbidden
B. willing
C. reluctant
D. forced