Miert nem mukodik?

Mindent igy csinaltam ahogy a srac mondta:

http://www.youtube.com/watch?v=4BE800B_afE

4:32 nel meg minden okes,de amikor le duplikaltam akkor nem alatta jelent meg hanem mellette:(

HTML:

<div id="container">

<div id="column_left">

<div class="column_left_box">

<h2> lorem ipsum dolor sit</h2>

<p>Lorem ipsum dolor sit amet, cs in faucibus orci luctus et ultrices eu ligula lorem. Fusce fermentum mi sed urna </p>

<p>Lorem ipsum dolor sit amet, cs in faucibus orci luctus et ultrices eu ligula lorem. Fusce fermentum mi sed urna </p>

</div>

</div>

<div id="column_left_box">

<h2> lorem ipsum dolor sit</h2>

<p>Lorem ipsum dolor sit amet, cs in faucibus orci luctus et ultrices eu ligula lorem. Fusce fermentum mi sed urna </p>

<p>Lorem ipsum dolor sit amet, cs in faucibus orci luctus et ultrices eu ligula lorem. Fusce fermentum mi sed urna </p>

</div>

</div>

<div id="column_right">njkhjbnihk</div>

<div class="clear"></div>

</div>

CSS:

div#container{

width: 760px;

margin: 0 auto;

background: white;

padding: 20px;

}

div#column_left{

width: 250px;

float: left;

margin:0 100px 0 0;

}

div#column_right{

width: 490px;

float:left;

}

div.clear{

clear:both;

}