It is important to know that we only use this expression informally.

重要的是要知道，我们只在非正式场合使用这个短语。

Another way to say it very informally is " I owe you one! "

我欠你一份人情！

Yes, you can use it informally; yes, you can use it in person.

是的，你可以在非正式的场合用它；是的，你可以在面对面交谈的时候用它。

The act of swimming naked is informally called skinny dipping.

裸着游泳这种行为被通俗地称为裸泳。

At the moment I work from home so I tend to dress fairly informally.

目前我在家工作，因此我倾向于穿得比较随意。

But this idiom is about learning something new by talking to people informally.

但是这个习语是指通过非正式的交谈来了解新的消息。

OK, but what if you want to greet someone informally?

好了，但是如果你想非正式地问候别人该怎么做呢？

Of course, speaking informally goes beyond word choice.

当然，非正式语言不仅限于词语选择。

Other translators chose to have Hagrid simply speak more informally, while others dropped his accent entirely.

其他语言的译者选择让海格用较轻浮的方式说话，虽然这样就完全捨弃掉口音。

You think I look too scruffy, and that I made a mistake by dressing too informally.

你认为我看起来太邋遢了，我搞错了场合，穿着太不正式。

This is common if you're answering the phone informally and you don't know who's calling.

这是非常常见的，如果在非正式的情形中接电话，并且你不知道谁打来的话。

More informally, you can also get into something.

更非正式地说，你也可以投资一些事情。

But informally, we call it " snot" .

我们有个不正式的说法，叫 snot。

Or more informally, " Listen, I've got to be off."

或者更非正式地说，“听着，先失陪了。”

Initially many of these transactions happened informally over social-messaging apps.

最初，许多此类交易都是通过社交通讯应用非正式进行的。

Or more informally, we simply say we are shocked or blown away.

或者更非正式地，我们就简单说" shocked（震惊）" 或者" blown away（震惊）" 。

But when we're speaking informally, we often use the simple past.

但是当我们在非正式场合说话时，我们通常会使用一般过去时。

And that's one of the really useful ways of saying " goodbye" informally.

这是非正式地说再见的一个非常有用的方式。

It's an expression we use informally to say something disastrous has happened.

这是一种表达方式，我们用这种非正式表达来形容发生了不幸的事。

The uncertainty between the two words probably comes when we use " house" informally.

但当我们在非正式场合下使用" house" 时，这两个词之间的不确定性可能会出现。