chance on 或 chance upon

To find or meet accidentally; happen upon

偶然找到，偶然遇到；偶然碰到

While in Paris we chanced on two old friends.

在巴黎我们偶然碰到两位老朋友

as chance would have it

as it happened

凑巧，偏偏

by any chance

possibly (used in tentative enquiries or suggestions)

万一，也许（用于试探性的询问或提议）

were you looking for me by any chance?.

你有可能是在找我吗？。

chance one's arm (或 luck)

(Brit. informal)undertake something although it may be dangerous or unsuccessful

(英，非正式)冒险一试

chance would be a fine thing

(informal)expressing a speaker's belief that something is desirable but the opportunity is unlikely to arise

(非正式)成功固然好，只惜良机少

no chance

(informal)there is no possibility of that

(非正式)绝无可能

on the (off) chance

just in case

万一

stand a chance

[usu. with negative]have a prospect of success or survival

有（成功或生存的）希望

his rivals don't stand a chance.

他的对手毫无成功的希望。

take a chance (或 chances)

behave in a way that leaves one vulnerable to danger or failure

冒险

take one's chance

do something risky with the hope of success

（为了成功而）冒险，碰运气

by chance

Without plan; accidentally

意外地；偶然地

They met by chance on a plane.

他们在飞机上不期而遇

Possibly; perchance

或许；可能

Is he, by chance, her brother?

他可能是她哥哥吗?

on the off chance

In the slight hope or possibility.

万一发生：抱着微小的希望或可能性