switch语句的几个疑问


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    <td background="images/top3.jpg">&nbsp;</td>
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        <td align="center"><a href="index.php?$lmbs=公司产品"><img src="images/gscp.gif" width="125" height="30" border="0" align="middle"></a></td>
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        <td align="center"><a href="index.php?$lmbs=企业管理"><img src="images/qygl.gif" width="125" height="30" border="0"></a></td>
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        <td align="center"><a href="index.php?$lmbs=下载专区"><img src="images/xzzq.gif" width="125" height="30" border="0"></a></td>
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        <td align="center"><a href="index.php?$lmbs=意见箱"><img src="images/yjx1.gif" width="125" height="30" border="0"></a></td>
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        <td align="center"><a href="index.php?$lmbs=资源管理"><img src="images/zygl.gif" width="125" height="30" border="0"></a></td>
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        <td align="center"><a href="index.php?$lmbs=公告栏"><img src="images/ggl1.gif" width="125" height="30" border="0"></a></td>
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        <td width="32" background="images/middle3.jpg">&nbsp;</td>
        <td width="581" align="center" valign="top"> <?php switch($lmbs){
case "":
    include "134.php";
break;
case "企业管理":
    include('room_add.php');
break;
case "下载专区":
    include "#";
break;
case "业务管理":
    include "#";
break;
case "意见箱":
    include "#";
break;
case "资源管理":
    include "#";
break;
case "公告栏":
    include "#";
break;
 }?></td>
        <td width="32" background="images/middle4.jpg">&nbsp;</td>
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</html> 这段代码是书上的，自己写的太长 没放上来 这段代码我测试过，不能载入room_add.php是为什么呢? 就是点那个企业管理，地址栏显示跳转到main_index.php?$lmbs=企业管理。但是显示的页面还是main_index的页面
当前页叫main_index.php