A simple selector is either a type selector or universal selector followed immediately by zero or more attribute selectors, ID selectors, or pseudo-classes, in any order.

一个简单选择符或者是一个类型选择符，或者是一个全局选择符，紧跟在后的是零个或多个属性选择符，ID选择符或伪类，次序任意。

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Using pseudo class selectors to change content?

使用伪类选择器来改变内容？

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Using pseudo class selectors to change content?

使用伪类选择器来改变内容？

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