如何使用Xpath提取特定的 元素？

There is a list:

有一个清单:

<ul class="params">
     <li> <span>Brand:</span> Casio </li>                  
     <li> <span>Gender:</span> male </li>           
     <li> <span>Material:</span> metal </li>
</ul>
<ul class="params">