单项选择题
A.小于80mg/LB.小于100mg/LC.小于120mg/LD.小于150mg/L
A.小于100mg/L(五天)B.小于80mg/L(五天)C.小于1500mg/L(五天)D.小于60mg/L(五天)
A.约8~10minB.约5~6minC.约6~10minD.约10~15min