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                            /Bootstrap
                        
                        /玩轉Bootstrap（基礎）

二級下拉菜單下沉，大神進來看看

<!DOCTYPE?HTML>
<html>
<head>
<meta?http-equiv="Content-Type"?content="text/html;?charset=utf-8">
<title>等分按鈕</title>
<link?rel="stylesheet"?>
<link?rel="stylesheet"?href="style.css">
<style>
????body{
????????margin-left:150px;
????????margin-top:200px;
????}
</style>
</head>
<body>
<ul?class="nav?nav-pills">
????<li?class="active"><a?href="##">首頁</a></li>
????<li?class="dropdown">
????????<a?href="##"?class="dropdown-toggle"?data-toggle="dropdown">教程<span?class="caret"></span></a>
????????<ul?class="dropdown-menu">
????????????<li><a?href="##">CSS3</a></li>
????????????<li><a?href="##">Sass</a></li>
????????????<li><a?href="##">jQuery</a></li>
????????????<li><a?href="##">Responsive</li>
????????</ul>
????</li>
????<li?class="dropdown">
?????????<a?href="##"?class="dropdown-toggle"?data-toggle="dropdown">關于我們<span?class="caret"></span></a>
????????<ul?class="dropdown-menu">
????????????<li><a?href="">Java</a></li>
????????????<li?class="nav-divider"></li>
????????????<li><a?href="">C#</a></li>
????????????<li><a?href="">C++</a></li>
????????????<li><a?href="">PHP</a></li>
????????</ul>
????</li>
</ul>
<script?src="http://img1.sycdn.imooc.com//down/53c6484f00013d9300000000.js"></script>
<script?src="http://maxcdn.bootstrapcdn.com/bootstrap/3.2.0/js/bootstrap.min.js"></script>?
</body>
</html>

二級菜單一樣的代碼為什么《關于我們》那一列卻下沉了呢？