万一

There is a supplementary water supply in case the rain supply fails.

主水源断, 我们另外有供水的地方。

Although the sun was shining,I took an umbrella to be on the safe side.

虽然有太阳,但我仍以防。

I took the precaution of locking money in the safe.

我把所有的钱都锁在保险箱里以防。

What if he's your rhumba boy?

他就是你伦巴男孩呢？

When the frequency changer has malfunction, power frequency is adopted, and the motor speed is nonadjustable.

变频器出现故障时，可工频驱动，转速不可调。

There will also be an 'underboss' who can run things should the 'boss' get thrown in the 'slammer'.

“头目”抓进“班房”,这里还有个“代理头目”来打理事情。