修改box4的bottom 无论数值大小都会跑到框3的下面，修改left没有反应
<!DOCTYPE HTML>
<html>
<head>
<meta http-equiv="Content-Type" content="text/html; charset=utf-8">
<title>相对参照元素进行定位</title>
<style type="text/css">
div{border:5px red solid;}
#box1{
width:200px;
height:100px;
position:relative;
}
#box2{
position:absolute;
top:10px;
left:10px;
}
/*下面是任务部分*/
#box3{
width:200px;
height:200px;
position:relative;
}
#box4{
width:94%;
position:absolute;
bottom:;
left:10;
}
</style>
</head>
<body>
<div id="box1">
<div id="box2">相对参照元素进行定位</div>
</div>
<h1>下面是任务部分</h1>
<div id="box3">
<img src="http://img1.sycdn.imooc.com//541a7d8a00018cf102000200.jpg">
<div id="box4">当我还是三年级的学生时是一个害羞的小女生。</div>
</div>
</body>
</html>
