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英语动词时态语态··达人进~

来源:学生作业帮 编辑:作业帮 分类:英语作业 时间:2024/09/13 19:22:33
英语动词时态语态··达人进~
in the past few years , many scientists_______ to find out why they failed in forecasting earthquakes
A.were trying
B. have been tried
C. have been trying
D . are trying
详解,谢
C.
in the past few years 意思是“在过去的几年里”,应该是从几年前开始一直到现在,故应该用完成时,(B项是被动语态.)have been trying是现在完成进行时,表示从过去某一时刻开始持续到现在并可能还要进行下去的动作.