-(往复一次)makearoundtrip;makeareturnjourney;gotoaplaceandcomeback:
makearoundtrip;打来回儿
Ittakeshalfanhourtogoonfootfrommyhometomyschoolandback.从我家到学校来回要走半小时。
-(往复多次)backandforth;toandfro:
oscillate;vacillate;来回摇摆
Heswambackandforthfivetimesupanddowntheswimmingpool.他在游泳池里游了5个来回。
-(周期;循环)cycle