例129　If railroads charged all customers the same average rate, they argue, shippers who have the option of switching to trucks or other forms of transportation would do so, leaving remaining customers to shoulder the cost of keeping up the line.

【结构分析】这句的条件状语从句是If railroads charged all customers the same average rate，句子的主干的主语是shippers，定语从句是who have the option of switching to trucks or other forms of transportation，修饰前面的主语，动词是would do，宾语是so，后面是分词状语leaving remaining customers to shoulder the cost of keeping up the line。

【亮点回放】此句话的亮点在于条件状语从句套上定语从句，这个定语从句很有想象力，把主语的特点说得很清楚，而且里面有分词状语，很经典。

【核心词汇】

charged all customers the same average rate　按同样的平均费率收取所有顾客的费用

switching to trucks or other forms of transportation　选择汽车运输或其他种类运输

shoulder the cost　承担成本

keeping up the line　保持收支平衡

【参考译文】铁路公司提出，按同样的平均费率收取所有顾客的费用，托运人肯定会选择汽车运输或其他种类运输，而不会选择铁运，那么铁运业内成本就只能由其他的铁运托运人来承担。