龙骨表面进行防锈,其双面镀锌量中优等品镀锌量为( )、一等品镀锌量为( )、合格品的镀锌量为( )。
120g/cm3,100g/cm3,80g/cm3
140g/cm3,120g/cm3,80g/cm3
140g/cm3,120g/cm3,100g/cm3
120g/cm3,110g/cm3,110g/cm3
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