A considerable amount of time and money has been invested in ______ this system.A.defining

学历类 成人英语三级 已帮助 人

A considerable amount of time and money has been invested in ______ this system.

A.defining

B.implying

C.reducing

D.perfecting

热搜:n维列向量组a1,an-1线性无关,且与非零向量正交

答案解析

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  • 正确答案:D
    解析:defining意为“定义”;implying意为“暗示”;reducing意为“减少”;perfecting意为“完善”。本句话意思是:完善这个系统。D项符合题意,如:They worked hard to perfect their dance.(他们卖力地使舞蹈更加完美)。