锚喷作业地点的总粉尘降尘效率应大于等于（）
A.70%
B.80%
C.85%
D.90%
参考答案：C
I’m tired, because I have homework.
A．too much, too many
B．much too , too much
C．much too, too many
D．too many , too much
艺术发现的心理特征
