0.6mm-0.7mm芯线线径的电缆一字型接续时需使用纸套管内径是()。 ["2.5mm","3.5mm","4.5mm","5.5mm"]
当油罐内的油品体积一定时,油品的密度越大,罐底受力()。 ["越小","越大","无关","不变"]
计算车站运输指标时,水陆联运货物在港口站的卸车,按()计算。 ["增加使用车","增加卸空车","装车数","卸车数"]
计算车站运输指标时,国境分界站向国外交出的重车或换装货物的卸车,按()计算。 ["增加使用车","增加卸空车","装车数","卸车数"]
油罐底受力的大小与罐内油品高度()。 ["成正比","成反比","无关","成二次曲线关系"]
购买决策的主要步骤?