有关于html的问题

.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;}