                        課程
                    
                        /前端開發(fā)
                        
                            /HTML/CSS
                        
                        /企業(yè)網(wǎng)站綜合布局實戰(zhàn)

我按視頻做的，圖片怎么樣都沒效果，請問這是哪里錯了

<!DOCTYPE?html>
<html?lang="en">
<head>
????<meta?charset="UTF-8">
????<title>Title</title>
????<link?href="css/main.css"?rel="stylesheet"?type="text/css">
????<script?src="js/setHomeSetFav.js"?type="text/javascript"?charset="GB2312"></script>
????<script?src="js/myfocus-2.0.4.min.js"?type="text/javascript"></script>
????<script?src="js/mf-pattern/mF_YSlider.js"?type="text/javascript"></script>
????<link?href="js/mf-pattern/mF_YSlider.css"?rel="stylesheet"?type="text/css"/>
????<script?type="text/javascript>">
????????myFocus.set({id:'picBox'})
????</script>
</head>
<body>
<div?class="top">
????<div?class="top_content">
????????<ul>
????????????<li><a?href="#">聯(lián)系我們</a>?</li>
????????????<li><a?href="#"?onclick="AddFavorite(window.location,document.title)">加入收藏</a></li>
????????????<li><a?href="#"?onclick="SetHome(window.location)">設(shè)為首頁</a>?</li>
????????</ul>
????</div>
</div><!--top結(jié)束-->
<div?class="wrap">
????<div?class="logo">
????????<div?class="logo_left">
????????????<img?src="images/logo.jpg"?alt="慕課網(wǎng)"/>
????????</div>
????????<div?class="logo_right">
????????????<img?src="images/tel.jpg"?alt="服務(wù)熱線"/>24小時服務(wù)熱線：<span?class="tel">123-456-7980</span>
????????</div>
????</div><!--logo結(jié)束-->
????<div?class="nav">
????????<div?class="nav_left"></div>
????????<div?class="nav_mid">
????????????<div?class="nav_mid_left">
????????????????<ul>
????????????????????<li><a?href="#">首頁</a></li>
????????????????????<li><a?href="list.html">關(guān)于慕課</a></li>
????????????????????<li><a?href="list.html">新聞動態(tài)</a></li>
????????????????????<li><a?href="list.html">課程中心</a></li>
????????????????????<li><a?href="list.html">在線課程</a></li>
????????????????????<li><a?href="list.html">人才招聘</a></li>
????????????????</ul>
????????????</div>
????????????<div?class="nav_mid_right">
????????????????<form?action=""?method="post">
????????????????????<label>
????????????????????????<input?type="text"?class="search_text"/>
????????????????????</label>
????????????????</form>
????????????</div>
????????</div><!--nav_mid結(jié)束-->
????????<div?class="nav_right"></div>
????</div><!--nav結(jié)束-->
????<div?class="ad"?id="picBox">
????????<div?class="pic">
????????????<ul>
????????????????<li><img?src="images/ad2.jpg"/>?</li>
????????????????<li><img?src="images/ad3.jpg"/></li>
????????????????<li><img?src="images/ad4.jpg"/></li>
????????????</ul>
????????</div>
????</div>
</div><!--wrap結(jié)束-->
</body>
</html>