/*任务部分*/
div.semi-circle{
height:100px;
width:50px;
background:#9da;
border-radius:50px 0 0 50px;
}
<!doctype html>
<html>
<head>
<meta charset="utf-8">
<title>border-radius</title>
<style type="text/css">
/*任务部分*/
div.semi-circle{
height:100px;
width:50px;
background:blue;
border-radius:50px 0 0 50px;
margin:10px;
}
div.shixing{
height:100px;
width:100px;
background:red;
border-radius:50px;
margin:20px;
}
div.you{
height:100px;
width:50px;
background:blue;
border-radius: 0 50px 50px 0 ;
}
div.shang{
height:50px;
width:100px;
background:red;
border-radius:50px 50px 0 0;
margin:10px;
}
div.xia{
height:50px;
width:100px;
background:red;
margin:10px;
border-radius:0 0 50px 50px;
}
</style>
</head>
<body>
<div class="circle">
</div>
<br/>
<!--任务部分-->
<div class="semi-circle"></div>
<div class="you"></div>
<div class="shixing"></div>
<div class="shang"></div>
<div class="xia"></div>
</body>
</html>
你可能是打错代码了， 0后面加px是完全可以的