Scientists say it may be five years it is possible to test this medicine on human patient

发布时间：2020-08-16 22:04:54

Scientists say it may be five years      it is possible to test this medicine on human patients．
A. since
B. until
C. before
D. when

网友回答

A. since
B. until
(答案→)C. before
D. when
解析：本题考查连词。句意：科学家说可能还要五六年才可能将此药试验在人身上。before引导时间状语从句, 表示 “过了……就”。
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