<section class="row">
<div style="background-color:yellow;" class="col-md-3 col-sm-3 col-xs-offset-3" >
左边
<section class="row">
<div class=" col-xs-6">1</div>
<div class=" col-xs-6">2</div>
</section>
</div>
<div style="background-color:orange;"class="col-md-6 col-sm-9">
中间
</div>
<div style="background-color:pink;"class="col-md-3 col-sm-12">
右边
</div>
</section>