I have a little money in the bank to fall back on.

我在银行还有一点钱，需要时可以动用。

He has her support to fall back on when the going gets tough.

当进展艰难时，他可以依赖她的支持。

When necessary, instinct is the most reliable resource you can fall back on.

必要时，本能是你可使用的最可靠的资源。

Doctors sometimes fall back on old cures.

医生们有时求助于传统疗法。

"I would fall back on her optimism, " he says.

“我彻底被她的乐观感染了，”他说。