如何将子菜单添加到导航菜单

我想完全设计一个菜单，该菜单看起来像下面的屏幕简短

我设计的菜单在以下屏幕快捷方式中

该菜单的HTML代码已给出

<div id='cssmenu'>
<ul>
    <li class='active'><a href='index.html'><span>WOMEN</span></a></li>
    <li><a href='#'><span>MEN</span></a></li>
    <li><a href='#'><span>JUNIOR</span></a></li>
    <li ><a href='#'><span>ACCESSORIES</span></a></li>
    <li><a href='#'><span>COLLECTION</span></a></li>

            <ul>
                <li><a href="#">item</a></li>
                <li><a href="#">item</a></li>
                <li><a href="#">item</a></li>
                <li><a href="#">item</a></li>
              </ul>

    <li><a href='#'><span>SALE</span></a></li>
    <li class="last"><a href='#'><span>MY ACCOUNT</span></a></li>

</ul>
                   </div>

然后给出CSS

@import url(http://fonts.googleapis.com/css?family=Open+Sans:700);
#cssmenu {
    background: #fff;
    width: 100%;
    border-bottom: 10px black solid;
    height: 49px;


}
#cssmenu ul {
  /*content: ' ';
  display: block;
  font-size: 0;
  height: 0;
  clear: both;
  visibility: hidden;*/

}
#cssmenu ul li {
  display: inline-block;
  padding: 0;


}
#cssmenu ul li a {
  color: #000;
  text-decoration: none;
  display: block;
  padding: 9.5px 25px;
  font-family: 'Open Sans', sans-serif;
  font-weight: 700;
  text-transform: uppercase;
  font-size: 14px;
  position: relative;
  float:right;
  border-bottom:10px solid #000 ;

}
.last {
    float:right;
    padding-left:60px;
    font-style:italic;
    }


#cssmenu ul li a:hover {
  color: #fff;
  border-color:#5ae1e4;
  background-color: #000;
  float:left;
}
#cssmenu ul li a:hover:before {
  /*width: 50%;*/
  border-color:#FFF;
}
#cssmenu ul li a:after {
  /*content: '';
  display: block;
  position: absolute;
  right: -3px;
  top: 19px;
  height: 6px;
  width: 6px;
  background: #ffffff;
  opacity: .5;*/
}
#cssmenu ul li a:before {
 /* content: '';
  display: block;
  position: absolute;
  left: 0;
  bottom: 0;
  height: 3px;
  width: 0;
  background: #333333;
  -webkit-transition: width .25s;
  -moz-transition: width .25s;
  -ms-transition: width .25s;
  -o-transition: width .25s;
  transition: width .25s;*/
}
#cssmenu ul li.last > a:after,
#cssmenu ul li:last-child > a:after {
  display: none;
}
#cssmenu ul li.active a {

}
#cssmenu ul li.active a:before {
  width: 100%;
}
@media screen and (max-width: 768px) {
  #cssmenu ul li {
    float: none;
  }
  #cssmenu ul li a {
    width: 100%;
    -moz-box-sizing: border-box;
    -webkit-box-sizing: border-box;
    box-sizing: border-box;
  }
  #cssmenu ul li a:after {
    display: none;
  }
  #cssmenu ul li a:before {
    height: 1px;
    background: #ffffff;
    width: 100%;
    opacity: .2;
  }
  #cssmenu ul li.last > a:before,
  #cssmenu ul li:last-child > a:before {
    display: none;
  }
}

问题是我看不到子集合我。请帮助我。先感谢您