【2012贵州铜仁】31.You ________ stop when the traffic light turns red.
A. can B. had better C. need D. must
【答案】D
【解析】本题考查情态动词的辨析。句意为：当交通灯变红，你“必须”停下来。根据语境可知此空意为“必须”，四个选项中，只有must具体有此意，故选D
【2012贵州毕节】30. When winter comes, days get ______.
A. long and long B. short and short C. longer and longer D. shorter and shorter
