Use hyphens to separate keywords.

使用连字符-分隔关键字。

No leading or trailing hyphens are permitted.

不允许使用前端或后端连字符。

The two parts are separated by two hyphens (" — ").

这俩部分通过两个连字号(“——”)分开。

Don't use hyphens in the domain if you can help it.

如果可能，就不要在域名中使用连子符“-”。

Substitute Spaces with hyphens or underscores (one or the other).

将空格替换为连字符或下划线(其中一种或另一种)。