16. He had already learned the news. I the trouble to phone him about it.
A. needn't have taken
B. could have taken
C. should have taken
D. mustn't have taken
网友回答
(答案→)A. needn't have taken
B. could have taken
C. should have taken
D. mustn't have taken
解析:可联系答.案.网客服索取。