twitter-bootstrap – 我应该放一个空列来腾出空间吗？

我在bootstrap中有一个两列的行.如何在列之间创建空间. – 我的第一个col是8,但是我想让它成为7并且只有1列作为空格.

这是我的bootply：
http://www.bootply.com/mwGajBOEVe

这是我的HTMl.

<div class="container">
    <div class="row">
        <div class="col-md-8">
            <p>The apple tree (Malus domestica) is a deciduous tree in the rose family best kNown for its sweet,pomaceous fruit,the apple.</p>
        </div>
        <div class="col-md-4"">
        The orange (specifically,the sweet orangE) is the fruit of the citrus species Citrus × sinensis in the family Rutaceae.</div>
    </div>
</div>

<div class="row">
  <div class="col-md-4">.col-md-4</div>
  <div class="col-md-4 col-md-offset-4">.col-md-4 .col-md-offset-4</div>
</div>
<div class="row">
  <div class="col-md-3 col-md-offset-3">.col-md-3 .col-md-offset-3</div>
  <div class="col-md-3 col-md-offset-3">.col-md-3 .col-md-offset-3</div>
</div>
<div class="row">
  <div class="col-md-6 col-md-offset-3">.col-md-6 .col-md-offset-3</div>
</div>