I was on the highway when this car went past followed 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：此题考查虚拟语气。根据句意，我对这辆车和紧随其后的警车的速度不能确定，只能推测。“must have been doing” 表肯定，推测车速至少在每小时150千米。易错点:C项意为“本来能……(暗示实际上没能或没做)”。