<div class="btn-group">
??? <button class="btn btn-default" type="button">首頁</button>
??? <button class="btn btn-default dropdown-toggle" type="button" data-toggle="dropdown">產品展示<span class="caret"></span> </button>
?????? <ul class="dropdown-menu pull-left">
?????????? <li><a href="#">收割機</a></li>
?????????? <li><a href="#">電動機</a></li>
?????????? <li><a href="#">拖拉機</a></li>
?????????? <li><a href="#">電動車</a></li>
?????? </ul>
??? <button class="btn btn-default" type="button">案例分析</button>
??? <button class="btn btn-default" type="button">聯系我們</button>
??? <button class="btn btn-default" type="button">關于我們</button>???
</div>