单项选择题
A.1个B.不设C.不少于2个D.2个
A.30~35m B.35~40m C.40~60m D.60m
A.1~2L/(m2⋅d) B.2~3L/(m2⋅d) C.1~3L/(m2⋅d) D.3~4L/(m2⋅d)