<div class="row">

  <div class="col-6">

    <select class="select">

      <option value="">No value</option>

      <option value="1">One</option>

      <option value="2" selected>Two</option>

      <option value="3">Three</option>

      <option value="4">Four</option>

      <option value="5">Five</option>

      <option value="6">Six</option>

      <option value="7">Seven</option>

      <option value="8">Eight</option>

    </select>

  </div>

  <div class="col-6">

    <select>

      <option value="">No value</option>

      <option value="1">One</option>

      <option value="2" selected>Two</option>

      <option value="3">Three</option>

      <option value="4">Four</option>

      <option value="5">Five</option>

      <option value="6">Six</option>

      <option value="7">Seven</option>

      <option value="8">Eight</option>

    </select>

  </div>

</div>

​