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

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詳解 (共 1 筆)

#1202217
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。
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