SOURCE

<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:red;"class="col-md-3 col-sm-12">
    右边
  </div>
  <div style="background-color:green;" class="col-md-3 col-sm-6">
    666
  </div>
  <div style="background-color:blue;" class="col-md-3 col-xs-6 col-sm-offset-3">
   888 
  </div>
  <div style ="background-color:black;" class="col-md-6 col-xs-6 col-sm-12">555</div>
</section> 
<section id="s1" class="row"> 
  <div style="background-color:pink;" class="col-md-6 col-xs-12">999</div> 
</section> 
<div class="col-xs-6 col-md-offset-3">
    <h1>咏鹅</h1>  
    <div class="row" >
        <div class="col-xs-6 col-md-offset-3" 
        style="background-color: yellowgreen;">
            <center><p>鹅鹅鹅，曲项向天歌</p>
              <p>白毛浮露水，红掌拨清波</p></center>
        </div> 
    </div>
</div>