She stood up and began to pace to and fro.她站起身，开始来回踱步。The boat was rocking gently to and fro in the water.小船在水中轻轻地来回摇荡。They travel to and fro between London and Paris.他们奔走于伦敦和巴黎之间....

adv.来回地，往复地...

to and fro的音标：to and fro的英式发音音标为：[tu: ænd frəʊ]to and fro的美式发音音标为：[tu ənd fro]...