off chance

n. 不大会有的机会(万分之一的希望, 侥幸)

例句与用法：

Stopped by on the off chance that they're home.

停下车看看，既使他们在家的可能性很小

I didn't think you'd be at home, but I just called on the off chance.

我想你不会在家的，只是抱著一线希望给你打个电话。

详细释义：

不容易有的机会; 极小之可能性

There is an off chance of finding her at home.

很少有希望在她家里找到她。