初三英语一题,by car,by bus,by后面不加the吧,为什么..

初三英语一题,by car,by bus,by后面不加the吧,为什么.. 为什么by car/bus不加冠词,但是by the bridge要加冠词? the children go to school by bus.为什么后面加do 不加does by bus 为什么中间不加冠词, By bus?No,by car. by后面加不加冠词?by bus等交通工具不加冠词,by analogy with也不加,是不是by后面都不用加冠词呢? 为什么by the car不对? 英语：The nurse's parents usually go to work by bus.(用by car 改为 we were surprised by the view为什么要加by不加by可不可以 by和交通工具之间是不是不加任何词 如:by car 没有by his car,by a car 英语作文People travel by plane,by train,by ship,by bus.To me,the by the bus对吗