Scientists say it may be ten years _____ this medicine was put to use.A since B before C after D.when 给出正确答案,理由和翻译
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Scientists say it may be ten years _____ this medicine was put to use.A since B before C after D.when 给出正确答案,理由和翻译
Scientists say it may be ten years _____ this medicine was put to use.
A since B before C after D.when
给出正确答案,理由和翻译
Scientists say it may be ten years _____ this medicine was put to use.A since B before C after D.when 给出正确答案,理由和翻译
选B.
后面的宾语是一个从句,before引导的时间状语从句,before this medicine was put to use 这种药物投入使用之前.
Scientists say it may be ten years when this medicine was put to use.
整句话意思是
科学家说10年后这种药物才能投入使用.
选B肯定不对的,请注意“this medicine was put to use”,谓语用的是过去时,那说明药已经投入使用了, 要说10年后这种药物才能投入使用,显然不通。如果要这么理解,句子应该改成 Scientists say it may be ten years before this medicine will be put to use.
正确答案是A,自从该药投入使用已来已...
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选B肯定不对的,请注意“this medicine was put to use”,谓语用的是过去时,那说明药已经投入使用了, 要说10年后这种药物才能投入使用,显然不通。如果要这么理解,句子应该改成 Scientists say it may be ten years before this medicine will be put to use.
正确答案是A,自从该药投入使用已来已经有10年,since引导时间状语从句。
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b原句是要表达在那个被使用前还需要二十年,a是自从的意思,不符c是在。。,之后,与题意相反d是那个时候,均不符合
before,科学家说这种药投入使用可能还需十年