是by plane or by train还是by plane or train

是by plane or by train还是by plane or train　　

有网友问，英语该说by plane or by train还是by plane or train？其实，两者都可以。当对by plane（乘飞机）、by train（乘火车）、by bus（乘公共汽车）等方式状语进行选择时，既可以在or后面重复介词by，也可以省略by。若用by plane or by train，说明是在by plane和by train中选择；若用by plane or train，则说明是有plane和train中选择。类似地如：　　

Are you going by sea or by air? 你打算坐船去还是坐飞机去? 　　

Do you hope to freight your belongings by air or sea? 你是想把东西空运去还是海运去? 　　

以下句子也属类似情况：　　

Did you contact her by email or fax? 你是用电子邮件还是用传真与她联系？　　

Had it happened by accident or by design? 那是偶然发生的还是人为让它发生的。　　

Do you think the house was burnt down by accident or design? 你认为房子是意外烧毁的还是有人故意放火的？　　

但是，如果两个短语所用的介词不一样，则不可省略。如：　　

Will you pay in cash or by credit card? 您是付现金还是刷卡？　　

Did he do so on purpose or by chance? 他这样做是有意的还是无意的?　　

Did he do it by accident or on purpose? 他做这事是偶然的，还是故意的?