Question

【题目】I was on the highway when this car went past followed by a police car. They ______ at least 150 km an hour.

A. should have been doing B. must have been doing

C. could have done D. would have done

Answer 1

【答案】B

【解析】本题考测情态动词的用法。must have done 表示对过去事情的推测，语气最强，意为：一定，肯定。本句意思是：那时候的速度肯定有150公里/小时。