問題詳情:
Scientists believe that it might be several years ______ the medicine can be used on human beings.( )
A.since B.when C.before D.until
【回答】
C
知識點:連詞
題型:選擇題
問題詳情:
Scientists believe that it might be several years ______ the medicine can be used on human beings.( )
A.since B.when C.before D.until
【回答】
C
知識點:連詞
題型:選擇題