我已将子菜单项添加到我的主菜单navigation，但它们根本没有显示?
我已经检查了css，没有看到任何隐藏子菜单的代码。
ul.art-hmenu {
display: inline-block;
vertical-align: middle;
padding-left: 13px;
padding-right: 13px;
}
ul.art-hmenu, ul.art-hmenu ul {
min-height: 0;
}
ul.art-hmenu, ul.art-hmenu ul {
display: block;
margin: 0;
padding: 0;
border: 0;
list-style-type: none;
}
table, ul.art-hmenu {
font-size: 12px;
font-family: Verdana, Geneva, Arial, Helvetica, Sans-Serif;
font-weight: normal;
font-style: normal;
}
.art-hmenu {
float: right;
}<ul class="art-hmenu menu-2">
<li class="menu-item-12 active"><a title="Home" href="http://agl.run-time.co.za/" class="active">Home</a> </li>
<li class="menu-item-14"><a title="Find Us" href="http://agl.run-time.co.za/find-us/">Find Us</a> </li>
<li class="menu-item-105"><a title="Facilities" href="http://agl.run-time.co.za/facilities/">Facilities</a> </li>
<li class="menu-item-207"><a title="Tours" href="http://agl.run-time.co.za/tours/">Tours</a> </li>
<li class="menu-item-229"><a title="Conferences" href="http://agl.run-time.co.za/conferences/">Conferences</a> </li>
<li class="menu-item-67"><a title="Contact" href="http://agl.run-time.co.za/contact/">Contact</a> </li>
<li class="menu-item-234"><a title="About Us" href="http://agl.run-time.co.za/about-us/">About Us</a> </li>
</ul>我忽略了什么或做错了，隐藏我的子菜单?
<ul class="art-hmenu menu-2">
<li class="menu-item-12 active"><a title="Home" href="http://agl.run-time.co.za/" class="active">Home</a>
</li>
<li class="menu-item-14"><a title="Find Us" href="http://agl.run-time.co.za/find-us/">Find Us</a>
<ul class="with-your-submenu-css-class">
<li><a href="">Submenu 1</a></li>
<li><a href="">Submenu 2</a></li>
<li><a href="">Submenu 3</a></li>
</ul>
</li>
<li class="menu-item-105"><a title="Facilities" href="http://agl.run-time.co.za/facilities/">Facilities</a>
</li>
<li class="menu-item-207"><a title="Tours" href="http://agl.run-time.co.za/tours/">Tours</a>
</li>
<li class="menu-item-229"><a title="Conferences" href="http://agl.run-time.co.za/conferences/">Conferences</a>
<ul class="with-your-submenu-css-class">
<li><a href="">Submenu 1</a></li>
<li><a href="">Submenu 2</a></li>
<li><a href="">Submenu 3</a></li>
</ul>
</li>
<li class="menu-item-67"><a title="Contact" href="http://agl.run-time.co.za/contact/">Contact</a>
</li>
<li class="menu-item-234"><a title="About Us" href="http://agl.run-time.co.za/about-us/">About Us</a>
</li>
</ul>
ul.art-hmenu {
display: inline-block;
vertical-align: middle;
padding-left: 13px;
padding-right: 13px;
}
ul.art-hmenu, ul.art-hmenu ul {
min-height: 0;
}
ul.art-hmenu, ul.art-hmenu ul {
display: block;
margin: 0;
padding: 0;
border: 0;
list-style-type: none;
}
table, ul.art-hmenu {
font-size: 12px;
font-family: Verdana, Geneva, Arial, Helvetica, Sans-Serif;
font-weight: normal;
font-style: normal;
}
.art-hmenu {
float: right;
}