The enemy fell back as our troops advanced.

我军部队挺进，敌军向后撤退。

The throng fell back, stupefied.

人群向后退去，惊呆了。

Instantly he disengaged himself, fell back a pace, and waited all attention.

他立刻挣脱出来，往后退了一步，全神贯注地等待着。

She fell back towards the end of the race.

赛跑快结束时她落后了。

He fell back onto the sofa in a drunken stupor.

他烂醉如泥，瘫倒在沙发上。