<!DOCTYPE html>
<html lang="en">
<head>
<meta charset="UTF-8">
<title>作业、雪碧图</title>
<style type="text/css">
.btu:link{
display:block;
height:55px;
width:50px;
background-image:url(作业.png);
background-repeat:no-repeat;
background-position:-8px -325px;
}
.btu:hover{
background-position:-55px -325px;
}
</style>
</head>
<body>
<a href="#" class="btu"></a>
</body>
</html>
