"moving back and forth or to and fro," late 14c., present participle adjective from rock (v.1). Of music, from 1949 (see rock (v.2)). Rocking-horse is first recorded 1724; rocking-chair is from 1766.
权威例句
1. The boat was rocking gently to and fro in the water.
小船在水中轻轻地来回摇荡。
2. He stood a few moments, rocking back and forwards on his heels.
他站了一会儿,踮着脚跟前后摇晃。
3. Judith was sitting in a rocking-chair by the window.
朱迪丝正坐在窗户边的一张摇椅里。
4. Chitty sat in his rocking-chair whittling wood.
奇蒂坐在摇椅上削着木头。
5. The seas are rising and the continents are rocking.