Scientists say it may be five or six years it is possible to test this medicine
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Scientists say it may be five or six years ________ it is possible to test this medicine on human patients．
[]A．since
B．after
C．before
D．when
试题答案
答案：C
解析：解析：考查一个常用句型It is…before…将要过……之后才能……，此句意为：科学家说有可能要过五、六年后这种药才能在人身上进行试验。 |