完形填空。（10分） It’s cold in winter. But it is also for many exciting sports; skating, skiing and sledding (雪撬). It is hard to skate and ski, but sledding doesn’t need. Now some sleds are made (制作) of glass, so they can move. In the old days, in some very parts of the world, people sleds to pull (拉) goods (货物) or people. Now sleds are used for exercising. After standing on a sled and kicking the ground, you can the sled. Or you can ask a person help. Another sled is called skeleton sled (骨架雪撬). It is. First, you your stomach (匍匐在上面) on a skeleton sled with your head ahead. Then you can drive it away. It is so fast that many people are afraid to ride it. they want again after it!