问题详情:
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
知识点:连词
题型:选择题
问题详情:
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
知识点:连词
题型:选择题