fro

Pat rolled the trolley to and fro.

帕特回推着手推车。

They travel to and fro between London and Paris.

他们奔走于伦敦和巴黎之间。

Wilkie watched the to and fro of their dancing.

威尔基看着他们回回地跳舞。

Those boats are prepared for waftage to and fro.

那些船舶是准备回运送货物。

In a huge sideways jumps called a grand jete, a skillful ballet dancer seems to float fro an impossible length of time.

在一种大幅度身跳跃动作（小跳）中，一个技艺精蕾舞演员好像在空中可以停上一段让人难以置信时间。

Another means of extracting DHEA is introduced,Extracting DHEA fro m the residue of sweet potato,namely,Dehydro epi androsterone.

介绍DHEA另一种提取方法,从红薯废料———薯渣中提取DHEA,即去氢表雄酮。