誰能幫我看下為什么下拉菜單點不開？要吐血了

<li?role="presentation"?class="dropdown">
??????<a?class="dropdown-toggle"?data-toggle="dropdown"?id="dropdownMenu1"?href="#">功能
????<span?class="caret"></span>
???</a>
????<ul?class="dropdown-menu"?role="menu"?aria-labelledby="dropdownMenu1">
????????<li?role="presentation"><a?role="menuitem"?tabindex="-1"?href="#">Action</a></li>
????????<li?role="presentation"><a?role="menuitem"?tabindex="-1"?href="#">Another?action</a></li>
????????<li?role="presentation"><a?role="menuitem"?tabindex="-1"?href="#">Something?else?here</a></li>
????????<li?role="presentation"><a?role="menuitem"?tabindex="-1"?href="#">Separated?link</a></li>
????</ul>
??</li>