关于html的问题

<div class="videonews_2">
 <img src="Images/light1.jpg" width="275px;" height="180px">
<div class="word_2">
    <p><a href="#">市关工委到文化市场调研学习相关经验</a></p>
    <span><a href="#"><img src="Images/bofang.gif" width="30"        height="30"></a></span>
  </div>
<div class="zhezhao">
</div> 
</div>

css

.videonews_2{ position:relative;}

.word_2{

width: 275px;
height: 50px;
background: rgba(0,0,0,0.7);
filter: alpha(opacity=70);
z-index: 1000;
position: absolute;
left: 0px;
top: 131px;



}
.word_2 p a{ display:block; color:#EEE; margin-left:10px; width:230px; margin-top:11px; line-height:15px; }
.word_2 span{

position: absolute;
left: 238px;
top: 11px;
z-index:1000;

} 

.zhezhao{

position: absolute;
width: 275px;
height: 180px;
background: rgba(0,0,0,0.8);
filter: alpha(opacity=80);
z-index: 1500px;
left: 1px;
top: 0px;
opacity:1;
 }    
 .word_2:hover .zhezhao{ opacity:0;}