如何使用WebDriver单击元素？

This is a piece of UI code

这是一段UI代码

<select id="order_unit_line_rate_806782_is_addenda_enabled" class="selects_for_487886" onchange="select_addendum(806782, this);dateShowMemory(this.options[this.selectedIndex].value, '806782');" uniqueattr="Dynamic Site Accelerator / Dynamic Site Accelerator / Additional Usage Commitment / drop down" name="order_unit_line_rate[806782][is_addenda_enabled]">
     <option value="0" uniqueattr="Dynamic Site Accelerator / Dynamic Site Accelerator / Additional Usage Commitment / Fee">                     Fee                   </option>
     <option value="1" uniqueattr="Dynamic Site Accelerator / Dynamic Site Accelerator / Additional Usage Commitment / See Attached Addendum">                     See Attached Addendum                   </option>
</select>
<select