I was on the highway when this car went past fol. Lowed by a police car. They at least 150 kilometers an hour.
A. should have been doing
B. must have been doing
C. could have done
D. would have done
网友回答
A. should have been doing
(答案→)B. must have been doing
C. could have done
D. would have done
解析：第一句话使用了一般过去时，由此可知第二句话是对过去事情的猜测，需用must have done.本题意为“我正在高速公路上行驶，这时一辆警车跟随着着这辆车从旁边经过。它们一定是以至少每小时150公里的速度行驶。”故选B。A项表示“本应该……”，C项表示“本能够……”不合题意。