為什么鼠標偏移上去之后,圖片不顯示呢?

.news_type_content{
height:?365px;
background:?url(../img/content_bg.gif)?repeat-x;
}
.news_type_content?li{
height:?30px;
line-height:?30px;
}
.news_type_content?li?a{
color:?#666;
background:?url(../img/li_bg.gif)?no-repeat?left?center;
padding-left:?15px;
display:?block;
}
.news_type_content?li?a:hover{
color:?#009CDF;
background:?url(../img/li_bg2.gif)?no-repeat?left?center;
background:?#F2F2F2;
}
2016-10-23
把最后那句改成background-color:#f2f2f2;就好了,原因是最后一句把上面那句覆蓋了