SOURCE

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

    <div style="background-color:red;"class="col-sm-3 col-xs-12">
    右边
  </div>
  <div>
  </div>
</section>
<section class="row">
    <div style="background-color:yellow;"class="col-sm-6 col-sm-push-6">
    左边
  </div>
    <div style="background-color:red;"class="col-sm-6 col-sm-pull-6">
    右边
  </div>
</section>