She rocked the baby to and fro.
她来回摇动着婴儿。
After some to-ing and fro-ing, Elsie and the children moved back to Louisiana.
几番往复后,艾尔西和孩子们搬回了路易斯安那。
Here the wind was roaring through the branches and the tree-tops were swaying to and fro.
风呼啸着吹过树枝,树冠来回摇摆。