He ________ without saying good — bye tothem, for he always has good manners.

He ________ without saying good — bye tothem, for he always has good manners.

A.mustn’t have left

B.may not have left

C.shouldn’t have left

D.can’t have left

答案及解析： D

can’t表示可能性最小，最不可能，因为后面说他总是很有礼貌。