I was on the highway this car went past followed by a police car. They at least 150 kilometers an hour.
A. when; should have been driving
B. while; would have driven
C. as; could have driven
D. when; must have been driving
网友回答
A. when; should have been driving
B. while; would have driven
C. as; could have driven
(答案→)D. when; must have been driving
解析：考查连词和情态动词用法。因为go past（经过）是短暂性动词所以不能与while连用，while只能和延续性动词连用。When既可以与短暂性动词也可以与延续性动词连用。第二空表示对过去某时正在发生情况的肯定推测。句意：当一辆汽车从我旁边经过，后面跟着一辆警车的时候，我正在高速公路上。他们当时的速度至少150公里每小时。