单项选择题
A.≤0.3/1000B.≤0.5/1000C.≤0.8/1000D.≤1.3/1000
A.≤0.10B.≤0.30C.≤0.50D.≤0.70
A.≤0.65B.≤0.50C.≤0.35D.≤0.20