html div 制作表格

[chenjia9695]

要的效果
为什么最后一个div不换行。怎么清空浮动的样式

<div>
    <div style=" background-color:#F00;">
        <div style="width:200px; height:100px; border:1px solid black; float:left"></div>
        <div style="width:200px; height:100px; border:1px solid black; float:left"></div>
        <div style="width:200px; height:100px; border:1px solid black; float:left"></div>
    </div>
    <div style="clear:left;" >
        <div style="width:200px; height:100px; border:1px solid black;  float:left;"></div>
        <div style="width:200px; height:100px; border:1px solid black; float:left"></div>
        <div style="width:200px; height:100px; border:1px solid black; float:left"></div>
    </div>
    <div style="height:100px;">
    
    </div>
</div>

[slwsss]

clear: both;清除float <div style="height:100px;clear: both;"> </div>