A型行为的特征是（） ["时间紧迫感","竞争敌意","脾气急躁","A、B、C都有","以上都不对"]
维生素B12的组成成分是（） ["铬","钴","铜","锌","硒"]
青盲的主要诊断依据是（） ["眼外观端好","视力下降明显","视野缺损","视神经乳头色淡","生理凹陷扩大"]
大跨度的工业厂房要采用（）结构。 ["砖木","砌体","钢筋混凝土","钢"]
青盲相当于现代医学之（） ["慢性青光眼","急性青光眼","黄斑变性","黄斑破孔","视神经萎缩"]
简述总成本分析法中要分析的物流活动。
