Coining a phrase is one thing, living up to it is another.

喊口号是一回事，而能否现却是外一回事。

It's another thing to move a historic home.

但把一栋历史悠久的房屋搬走是外一回事。

Collecting as a serious hobby is quite different and has many advantages.

作为一种严肃的业余爱好的收藏活动完全是外一回事，它具有许多益处。

Whether he can maintain stable trade relations with America is another matter.

他是否可以维系与美国的稳定贸易关系又是外一回事了。

Whether it could actually be done is another matter.

然而这种做法能否践又是外一回事。

If we could rejuvenate, of course it would be different. But we can't.

我们如果能够返老还童，那又是外一回事了，可惜办不到。

Yes, but it's different actually seeing it.

是，但是际看到又是外一回事。

But the speed of light, the light barrier, that's a very different story.

但要说到“光障”，那可就是外一回事了。

But airships were something else entirely.

但是飞艇完全是外一回事。

While liquid water is no longer stable on Mars, frozen water, ice, is a different story.

虽然液态水在火星上不再稳定，但冰冻的水，冰，就是外一回事了。

But he went on to say quote again whether they affected the outcome is another question.

但他还表示是否影响了选举结果是外一回事。

You know, there's pretending to be mother, and then, there's reality. Let's not push our luck, ok?

你要知道，想做好妈妈是一回事，际情况又是外一回事了。我们不要太勉强，好吗？

It is another thing for people to say that our demands are too aspirational.

家说我们要求太高又是外一回事。

It is all these things, but it is something else.

它是所有这些东西，但它是外一回事。

We're not very proud, but that's a whole other story.

我们不是很自豪，但那是外一回事了。

Well, here, we're not talking about apostrophes and possessions, this is something else.

好吧，在这里，我们不是在谈论撇号和所有物，这是外一回事。

I once knew a Sister Ursula, but that's a different story.

我曾经认识一位厄休拉修女，但那是外一回事了。

There was also an English rock band called Dire Straits, but that's a different story.

还有一个英国摇滚乐队叫做 Dire Straits，但那是外一回事了。

A group of lions is another matter, but this hippopotamus is fearless, unpredictable and angry.

一群狮子又是外一回事，但这头河马却无所畏惧、难以预测而且愤怒。

As for the grave there being as quiet as you mention, it is another matter.

至于像你说的坟墓那里安静，那就是外一回事了。