单项选择题
A.余弦B.反比C.正弦D.正比
A.0.6~0.8B.0.8~1.0C.0.2~0.4D.0.6~1.0
A.3mg/LB.2mg/LC.5mg/LD.4mg/L
A.9.4~10.6B.6.4~8.2C.4.4~6.2D.3.1~4.4
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