跳汰用水的浓度应不超过()克/升
A:100
B:70
C:60
D:60
参考答案:C
May is ______ month of the year. [ ]
A. five
B. fifth
C. fourth
D. the fifth
让受试者对某些意义不明的图形作出回答是( )
A.问卷法B.作业法C.投射法D.墨迹法E.图像法