Ateamofscientists
来源:语文精选馆 2.71W
问题详情:
A team of scientists _____ the effects of acid rain over the last twenty﹣year period.( )
A.studied B.had studied
C.is studying D.has been studying
【回答】
D
知识点:动词时态与语态
题型:选择题
问题详情:
A team of scientists _____ the effects of acid rain over the last twenty﹣year period.( )
A.studied B.had studied
C.is studying D.has been studying
【回答】
D
知识点:动词时态与语态
题型:选择题