单项选择题
A.2mg/l B.0.2mg/l C.0.02mg/l D.0.002mg/l
A.氯丁橡胶 B.丁基橡胶 C.丁腈橡胶 D.氟橡胶
A.55% B.65% C.75% D.80%
A.≤1mg/l B.≤5mg/l C.≤10mg/l D.≤15mg/l
微信扫一扫,加关注免费搜题
