問題詳情

19.He ___ aeronautics at the Air Force Institute of Technology for more than twenty years.
(A) has been teaching
(B) is teaching
(C) has been taught
(D) taught

參考答案

答案:A
難度:適中0.4
統計:A(14),B(5),C(12),D(3),E(0)

內容推薦