In the past twelve months the research m
题型:选择题
问题:
In the past twelve months the research members ______ the effectiveness of many materials in a home building.
A.had studied
B.would study
C.studied
D.have studied
In the past twelve months the research members ______ the effectiveness of many materials in a home building.
A.had studied
B.would study
C.studied
D.have studied