fall back on片语动词

依靠、求助于、依赖

If the business fails, she can always fall back on teaching.

如果生意失败，她还可以靠教书维生。

退回到、重拾

Under pressure, he fell back on the same tired excuses.

压力一大，他又退回到那些老掉牙的借口。

备用方案、退路、后备选择

We need a fallback in case the funding never arrives.

万一资金迟迟不到，我们需要一个备用方案。

备用的、后备的

The system switches to a fallback server during maintenance.

维护期间系统会切换到备用伺服器。