adv.向那边,向后;
例句:
He grew weary of running to and fro on the short track.
他开始对在这节短轨道上开来开去有些厌倦了.
Branches waved wildly to and fro.
树枝猛烈地摇来摇去.
The flower seemed to quiver, and then swayed gently to and fro.
花儿似乎在颤动, 接着轻轻地来回摇摆.