ph.

1. The wind moved the trees gently back and forth.
风吹来，树来回轻摆。

1. 来回地,反复地：at times 有时,间或 | back and forth 来回地,反复地 | back of 在......后面

2. (前后)来回地,往返：attend to 专心;照顾,护理 | back and forth (前后)来回地,往返 | back away 逐渐后退

3. (前后)来回地,反复地：at the same time同时;然而,不过 | at the sight of一看见......就 | back and forth(前后)来回地,反复地

adv

1. moving from one place to another and back again

e.g. he traveled back and forth between Los Angeles and New York
the treetops whipped to and fro in a frightening manner
the old man just sat on the porch and rocked back and forth all day

Synonym: backward and forwardto and fro