单项选择题
A.5000m3/h B.7000m3/h C.9000m3/h D.12000m3/h
A.高压、直流、不均匀 B.高压、直流、均匀 C.低压、直流、均匀 D.高压、交流、均匀
A.每层 B.每隔1~2层 C.每隔2~3层 D.每隔3层