副詞 back and forth:

1. moving from one place to another and back again
   同義詞：backward and forward, to and fro

1. A jump in ballet during which the dancer crosses the legs a number of times, alternately back and forth.
   空中交叉跳躍一種芭蕾舞動(dòng)作，舞者在空中多次前后交叉雙腿
2. He fluttered back and forth in the corridor.
   他在走廊上煩躁不安地走來(lái)走去。
3. The guard walked back and forth in front of the gate.
   警衛(wèi)在大門前走來(lái)走去。
4. He rocked back and forth in his rocking chair.
   他坐在搖椅里前后搖晃著。