万一的英文：
in case
by any chance
contingency

参考例句：

In case of fire, ring the alarm bell.
万一失火的话，请按警铃。

If something should go wrong, the signal lamp would light up
万一发生什么事故，信号灯就会亮起来

It would be very unseemly if the corpses had to put on immortality under the gaze of mere sight-seers
万一游客正在参观的时候，那些木乃伊在他们眼前一下子都进入永生的境界，岂不是很尴尬吗？

Had the poor man been apoplectic, he could never have recovered from his paroxysm of wrath
说真话，这个老实人要是万一现在带着这股气劲中风晕过去了，那他准不会再活过来了。

If peradventure you fail.
万一你失败了。

It’s always wise to play safe.
不怕一万就怕万一

Should there be a flood, what should we do?
万一发生水灾我们怎么办？

If it should rain, our plan would Be spoiled.
万一下雨，我们的计划就泡汤了。

Call the police in the event of an emergency.
万一紧急情况就打电话给警察。

In the event of emergency we may make off.
万一发生紧急情况，我们可以逃的。

chance是什么意思：
n. 机会；可能性；偶然，侥幸
adj. 意外的，偶然的
v. 碰巧；偶然发生；偶然发现；冒...的险

I advise you to take the chance.
我建议你抓住机会。

outside chance; remote possibility.
不大可能的机会；极小的可能性。

I'll afford you a chance.
我将给你提供一个机会。

A lost chance never returns.
错过的机会永不再来。

Why not take a chance on it?
为什么不冒险一试呢？

contingency是什么意思：
n. 突发事件，意外事故；可能性，偶然性；意外开支

History is contingent.
历史是偶然的。

They cont on it as the place where they can relax and prepare themselves for the negotiations ahead.
他们把希尔顿宾馆当作是放松自己为一轮轮的洽谈作好准备的场所。

Economic efficiency indicators of industrial enterprises I (Cont'd)
工业企业主要行业经济效益指标I(续)

They are the backbone of the scientific and technological contingents.
他们是科技队伍的骨干力量。

The contingent marched in the direction of the Western Hills.
队伍朝西山的方向前进。