問題詳情
36. With the help of high technology, more and more new substances ______ in the past years.
(A) discovered
(B) have discovered
(C) had been discovered
(D) have been discovered
參考答案
答案：D
難度：適中0.5
統計：A(0),B(0),C(0),D(0),E(0)
用户評論
【步筱昕】評論
由句中的时间状语in the past years可知，空格应填现在完成时；又因句子中的主语new substances与discover为被动关系，故选D项。