``` <!--执行顺序从外到内,也就是外层的条件不满足,就算里层的条件满足了,也不会执行里层的缓存操作--> <?php if($this->beginCache('cache_div',['duration'=>20])){?> <div id="cache_outer_div"> <h1>这里是外层,会被缓存999</h1> <?php if($this->beginCache('cache_inner_div',['duration'=>1])){?> <div id="cache_inner_div"> <h1>这里是内层,会被缓存555</h1> </div> <?php $this->endCache(); }?> </div> <?php $this->endCache(); }?> ```