单项选择题
A.1/10~1/20 B.1/20~1/40 C.1/40~1/60 D.1/10~1/30
A.由罐的容积 B.由罐底面积 C.由罐底直径 D.可任意
A.2~4 B.4~6 C.6~8 D.4~8
A.A3 B.A3F C.16MnR D.BMnVR
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