I ______ have been more than six years old when the accident happened.
A. shouldn’t B. couldn’t C. mustn’t D. needn’t
I ______ have been more than six years old when the accident happened.
A. shouldn’t B. couldn’t C. mustn’t D. needn’t
B
本题考查情态动词的用法。must表示推测只能用于肯定句，否定句用can或could 代替。shouldn’t have done 表示“本来不该而实际上却做了某事”.needn’t have done表示“本来不必而实际上却做了”均不合题意。