如下代碼，顯示異常，如果去掉公用左浮動類fl而改成在fist_class和limit兩個類中單獨添加左浮動屬性則顯示正常，因此疑問這兩種設置浮動的方式有何區別？??? ????????<div class="select_content">?? ??? ??? ??? ??? ?<dl >?? ??? ??? ??? ??? ??? ?<dt class="fist_class fl"><a href="#" >手機</a></dt>?? ??? ??? ??? ??? ??? ?<dd class="limit fl"><a href="#">不限</a></dd>?? ??? ??? ??? ??? ??? ?<dd class="select_det">?? ??? ??? ??? ??? ??? ??? ?<ul >?? ??? ??? ??? ??? ??? ??? ??? ?<li><a href="#" >Samsung/三星</a></li>?? ??? ??? ??? ??? ??? ??? ??? ?<li><a href="#" >Samsung/三星</a></li>?? ??? ??? ??? ??? ??? ??? ??? ?<li><a href="#" >Samsung/三星</a></li>?? ??? ??? ??? ??? ??? ??? ??? ?<li><a href="#" >Samsung/三星</a></li>?? ??? ??? ??? ??? ??? ??? ??? ?<li><a href="#" >Samsung/三星</a></li>?? ??? ??? ??? ??? ??? ??? ?</ul>?? ??? ??? ??? ??? ??? ?</dd>?? ??? ??? ??? ??? ?</dl>?? ??? ??? ??? ?</div>