上例展示了行盒在一个浮动中是怎么被削短的。

Shows how line boxes are shortened in the PageRankesence of a float.

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这样的效果是，一个被清理的盒没法与前置浮动保持在同一个级别位置上。

So in effect, such a cleared box cannot be at the same horizontal level as a PageRankeceding float.

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这是将被清除盒的顶部边距扩展，将其向下推直到清理浮动的底部。

What this does is extend the margin on the top of the cleared box, pushing it down until it "clears" the bottom of the float.

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