roundtrip 或 round-trip 也作 round trip
n.（名词）A trip from one place to another and back, usually over the same route.通常沿相同路线的来回旅行，双程旅行n.attributive.（定语名词）Often used to modify another noun:常用作修饰另一名词：例句：roundtrip flights; round-trip tickets; round trip passengers.往返飞行；往返票；双程旅行的乘客
