所有空元素必须使用xml空标记语法，在右括号前有一个结尾的正斜杠(例如，becomes)。

All empty elements must use the XML empty tag syntax with a trailing forward slash before the end bracket (for example, becomes).

youdao

但你可以想象一个字距配对为正的例子：一个小写f后跟随一个括号，例如：“f”。

But you can also imagine a positive kerning pair when a 'f' is followed by a bracket for example; "f".

youdao

So that's just a little bit of a check for yourself, and it should make sense because what you're doing is you're calculating the difference between energy levels, so you just need to flip around which you put first to end up with a positive number here, and that's a little bit of a check that you can do what yourself.

所以你们总要确保括号，离得这项是正的，这是你们自己,可以做的检查，这事很有道理的，因为你们做的是计算能量差,所以你需要调整顺序来保证一个正数，这是你们自己可以做的检查。

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