—You realize that you were driving at 100 mph, don’t you?
—No, officer. I ______. This car can’t do more than 80.
A、didn’t need to be
B、may not have been
C、couldn’t have been
D、needn’t have been
【正确答案】：C
【题目解析】：这儿指的是刚才不可能以每小时100英里的速度行驶，说的是发生在过去的事，所以排除A，A to 后是动词原形，此处要用have done 表发生在过去的事。B,C,D 之间是情态动词的区别，may 的可能性很小，needn't 是不必的意思，只有couldn't 表示不可能
