要用bootstrap做一个侧边栏还要能展开二级菜单，求问大神们怎么做？

Question

<div class="form-group col-md-6 col-sm-6" style="width:30%"> <label class="col-sm-4 control-label" style="text-align: left"><h4><strong>有偿使用:</strong></h4></label> <div class="col-sm-8"> <select class="form-control" name="sy"> <option value="1">计费</option> <option value="2">收费</option> </select> </div> </div> <div class="form-group col-md-6 col-sm-6" style="width:30%"> <label class="col-sm-4 control-label" style="text-align: left"><h4><strong>有偿退出:</strong></h4></label> <div class="col-sm-8"> <select class="form-control" name="tc"> <option value="1">补偿</option> <option value="2">补助</option>   </select> </div> </div>这是之前写成下拉菜单，求问大神们改成侧边栏。跪求！