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

我想你不会在家，只是碰碰运气顺路来看一下。

《牛津词典》

You once had a chance, but you lost it!

你曾经有机会，但是你错过了它！

youdao

Mr. X hated the dead person and wanted to kill him, but had no chance.

X 先生恨这个死人，想杀了他，但是没有机会。

youdao

But an explosion in space cost him the chance to reach the moon -- and nearly cost the crew their lives.

VOA: special.2010.04.28

There was not fancy, but having a chance, having a beauty together, sitting down around the table, being presented with graduation certificates gradually and individually.

没有幻想，但借此机会，所有人度过了美好时光，他们围坐在桌前，一个一个地,颁发毕业证书。

麻省理工公开课 - 媒体、教育、市场课程节选

But it's really a chance, especially for those less comfortable, to be set off on a very specific path.

这的确是一个机会，特别对于那些不怎么舒适的，这是通过,特殊途径开始的好机会。

哈佛公开课 - 计算机科学课程节选

But a chance sighting of her own face in the rear view mirror changed her outlook completely.

CNN: Diana Nyad making fourth attempt at Cuba-to-Florida swim

But a chance encounter with dancer Gregory Hines, who was on the lookout for old-time Pittsburgh dancers, got Belcher dancing again.

NPR: StoryCorps Griot: Dancing Feet

"He's been doing a great job, but any chance I have to get him, I'm going to, " Ryan said.

WSJ: Geno Smith gives himself 'F' for 1st Jets practice