通读下面短文，掌握大意，然后在各题所给的四个选项中选出一个最佳答案。
Winter is dangerous because it's so difficult to know31.___ is going to happen and 32.___ take place so easily. Fog can be waiting to33.__ you over the top of a hill.34.__ might be hiding under the melting （融化）snow.waiting ahead （前面）to send you 35.____ the road. The car coming to you may suddenly slip36.____ the road.
Rule Number One for37.___ on icy roads is to drive smoothly （平稳地）.Sudden movements 38.___ make a car very difficult to39.___. So every time you40.___ start or stop your car.41.____ or reduce your speed.you must be42.___ gentle and slow as possible. Suppose you are driving with a full cup of hot coffee on the seat next to you. Drive so that you wouldn't spill （溅）it.
Rule Number Two is to43.___ attention to what might happen. The44.___ ice there is， the further down the road you have to look. Test 45._____ it takes to gently stop your car. Remember that you may be driving more quickly than you think. Generally.allow twice of your usual stopping distance when the road is wet.three times this distance on snow.and even more on ice. Try to stay in control of your car at all time and you will not get into trouble.
31. A. when B.what C. why D. how
32. A.things B. stories C.accidents D. hurt
33. A.meet B.see C.wait D. watch
34. A. rain B. waterC. ice D. wind
35. A.off B. on C.for D. with
36. A.through B.in C. below D. across
37. A.riding B. walking C. playing D. driving
38. A.must B. can C. have to D. need
39. A.control B. manage C. start D.understand
40.A another B. other C. either D.neither
41.A.provide B. increase C.offer D.suplly
43.A. fly B. pay C. go D. stop
44.A. best B.good C. better D.more
45.A.how far B. when C.how long D.how much
答案：BCACA DDBAC BABDC