退票费按（）计算。 ["每张车票金额的20%","每张车票金额的5%","每张车票金额的10%","每张车票金额及退票时距票面开车时间梯次"]
Eventually chemical changes（）the generation of petroleum. ["hand in","give in","take in","result i"]
登记簿必须根据真实、合法、有效的内容记载，做到（）。 ["内容完整","数字准确","字迹清楚","不得弄虚作假"]
在车站上补票的手续费为（）。 ["2元\/人次","3元\/人次","4元\/人次","5元\/人次"]
直埋光缆与管径于30-50厘米铁道路轨外侧之间平行隔距不小于（）米。 ["0.5米","0.75米","1米","2米"]
简述CRH2A型动车组辅助供电系统的工作原理。
