老师，为什么我这个不能实现简单图片展示？
<!DOCTYPE html PUBLIC "-//W3C//DTD XHTML 1.0 Transitional//EN" "http://www.w3.org/TR/xhtml1/DTD/xhtml1-transitional.dtd">
<html xmlns="http://www.w3.org/1999/xhtml">
<head>
<meta http-equiv="Content-Type" content="text/html; charset=gb2312" />
<title>无标题文档</title>
<style type="text/css">
#wrap{
width:400px;
height:240px;
margin:0 auto;
background:url(图片/xuan5.jpg) no-repeat;
position:relative;
}
span{
position:absolute;
bottom:0px;
left:0px;
width:400px;
filter:alpha(opacity=60);
opacity:0.6;
font-family: "新宋体";
color: #FFFFFF;
text-align:center;
font-size: 24px;
background-color: #000000;
display:none;
}
a:hover{
border:1px solid #003399;
}
#wrap a:hover span{
display:block;
}
</style>
</head>
<body>
<div id="wrap">
<a href="http://chs.nuomi.com/?lf=2"><span> 勤能补拙</span></a>
</div>
</body>
</html>
