<div id="main-container">
<div class="box">apple</div>
<div class="box">bus</div>
<div class="box">cattle</div>
<div class="box">dog</div>
<div class="box">eggplant</div>
<div class="box">fox</div>
<div class="box">goat</div>
</div>
如何在“#main-container”中找到最后两个“.box”,然后为它们分配特定的类?