col-lg-4 col-md-4 col-sm-12 col-xs-12
<div class="row">
<div class="col-lg-4 col-md-4 col-sm-12 col-xs-12">
lg=4 md=4 sm=12 xs=12
</div>
</div>
依次是大,中,小,更小
<div class="row">
<div class="col-lg-4 col-md-4 col-sm-12 col-xs-12">
lg=4 md=4 sm=12 xs=12
</div>
</div>
依次是大,中,小,更小