Everypossiblemeans

問題詳情：

Every possible means_____, but the teacher as well as the students _____worked out the math problem yet .

A. has tried ; haven’t         B. have tried; haven’t

C. has been tried; hasn’t      D. have been tried; hasn’t

【回答】

c

知識點：現在完成時及其被動式

題型：選擇題