Most young people enjoy some form. of physical activity. It may be walking, cycling or swimming, in winter, or skating or skiing. It may be a game of some kind — football, hockey, golf or tennis. It may be mountaineering. These who have a passion【C1】______climbing high and difficult mountains are often【C2】______with astonishment. Why are men and women【C3】______to suffer cold and hardship, and to【C4】______on high mountains? This astonishment is caused, probably, by the difference between mountaineering and other forms of activity【C5】______which men give their leisure. Mountaineering is a sport and not a game. There are no man-made roles, as there are for【C6】______games as golf and football. There are, of course, rules of different kinds which it would be dangerous to【C7】______, but it is this freedom from man-made rules【C8】______makes mountaineering attractive to many people. Those who climb mountains are free to use their own【C9】______. If we【C10】______mountaineering with other more familiar sports, we might think that one big difference is【C11】______mountaineering is not a' team work'. We should be mistaken in this. There are, it is true, no 'matches'【C12】______'teams' of climbers, but when climbers are on a rock face linked by a rope on which their lives may【C13】______, 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【C14】______of nature. His sport requires high mental and【C15】______qualities. A mountain climber【C16】______to improve in skill year after year. A skier is probably past his best by the age of thirty, and most international tennis champions【C17】______in their early twenties. But it is not【C18】______for men of fifty or sixty to climb the highest mountains in the Alps. They may take more【C19】______than younger men, but they probably climb with more skill and less【C20】______of effort, and they certainly experience equal enjoyment. 【C1】