He ________ without saying goodbye to them, for he always has good manners .

A.mustn't have left

B.may not leave

C.shouldn't have left

D.can't have left

答案及解析： D

解析：

导解：没有向他们告别，不会离开．否定的推测，从后半句可知他很有礼貌，所以应用can't．