Code: http://jsfiddle.net/74y7h/
When I float:left the item-content div, suddenly margin-bottom no longer works on each of the items in the list. Remove the float:right line and re-run the code and you ll see the margins reappear between the list items.
为什么发生这种情况? 我不需要一个完整的教训,但希望能简单地解释一句话或两句,而不仅仅是固定句子。 感谢!