定路線的用法和樣例：
例句
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（固定路線的）運輸系統通常有固定路線的公有或私有貸運或客運系統，如船運、空運或汽運
A passenger or cargo system of public or private transportation, as by ship, aircraft, or bus, usually over a definite route. -
公共汽車一種載客的長型機動車輛，通常沿指定路線行駛
A long motor vehicle for carrying passengers, usually along a fixed route. -
我們偏離原定路線走了好幾英里。
We went some (ie several) miles out of our way.
