资料：Most young people enjoy some form of physical activity. It may be walking, cycling or swimming, or in winter, skating or skiing. It may be a game of some forms, football, hockey, golf, or tennis. It may be mountaineering.
Those who have a passion for climbing high and difficult mountains are often looked upon with astonishment. Why are men and women willing to suffer cold and hardship, and to take risks on high mountains? This astonishment is caused probably by the difference between mountaineering and other forms of activity to which 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 , of course, rules of a different thing that it would be dangerous to ignore, but it is this freedom from man-made rules that makes mountaineering attractive to many people. Those who climb mountains are free to use their own methods.
If we compare mountaineering and other more familiar sports, we might think that one big difference is that mountaineering is not a 'team game'. We should be mistaken in this. There are ,it is true, no 'matches' between 'teams' of climbers, but when climbers are on a rock face linked by a rope on which their lives may depend, there is obviously teamwork.
The mountain climber knows that he may have to fight forces that are stronger and more powerful than men. 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 his best by the age of thirty, and most international tennis champions are in their early twenties.But it is not unusual for man 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 waste of effort, and their certainly experience equal enjoyment.
Mountaineers compete against ___.
本题考查的是细节理解。
【关键词】mountaineers;compete;against
【主题句】第5自然段The 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. 登山者知道，他可能不得不与比人更强壮更强大的力量作战。他必须对抗自然的力量。
【解析】本题的问题是“登山者要与什么对抗？”。选项A意为“自然”；选项B意为“彼此”；选项C意为“其他球队”；选项D意为“国际标准”。
根据主题句可知，登山者需要对抗自然的力量，故选A。
下列关于公司的表述，正确的是（）
以下各项列举了我国常见气象灾害与其发生地区的对应关系，其中正确的一项是（）
根据电视收视率调査，看体育节目的观众中青年人比中老年人要多。
由此可推断出（）
—种海洋蜗牛产生的毒素含有多种蛋白，把其中的一种给老鼠注射后，会使有两星期大或更小的老鼠陷入睡眠状态，而使大一点的老鼠躲藏起来。当老鼠受到突然的严重威胁时，非常小的那些老鼠的反应是呆住，而较大的那些老鼠会逃跑。
以上陈述的事实最有力地支持了以下哪项假说？（）
疾病控制中心对某校髙中三个年级的学生进行抽样做视力状况调查，抽样的方法为分层抽样（按比例抽样），若高中一、二、三年级学生人数分别为626、703、780，样本容量为84，则应从离二年级抽样的学生人数为多少？（）
