Being responsible for one's own health is one thing, but being responsible for another person's health is quite a different matter.

对自己的健康负责是一码事，但对别人的健康负责完全是另一码事。

《柯林斯英汉双解大词典》

For one thing, I firmly believe that reading can increase our knowledge. For another, reading helps us to calm down when we feel upset.

首先，我坚信阅读能增加我们的知识。另一方面，当我们感到沮丧时，阅读帮助我们平静下来。

youdao

Don't set him the task. For one thing he's old; for another he's in poor health.

不能让他去干，一则年纪大，二则身体弱。

《新英汉大辞典》

For the next eight years, he tried one thing after another.

VOA: special.2010.02.11

In the grammatical sense, this word is the means or principal of predication whereby we say one thing is another thing: the mare is the female of the horse, for example.

从语法的角度来看，is这个词是,我们声明一个东西是另一个东西的方式或者？委托：,例如说，母马是马中的雌性。

耶鲁公开课 - 文学理论导论课程节选

"For one thing to be believable we needed to push another story line even further.

VOA: standard.2010.02.27

And not all of them came out profitable because of a methodology that inflates operating margin. (The median margin was negative 0.27%.) A given local hospital may have good operations, but not feel profitable because almost every cent of its profit is sent to their parent system for one thing or another.

FORBES: Profitable Hospitals To Forbes: Who Me?

It's one thing cutting the jigsaw but it's totally another thing for it to dismantle itself.

BBC: Diamond Jubilee Jigsaw of 40,000 pieces breaks

Since when is the idea that we look out for one another a bad thing?

WHITEHOUSE: President Obama Speaks on the Resurgence of the American Auto Industry | The White House