这有一小段代码，看不太懂，帮小弟我解释一下，多谢拉

<{require file="block/header.html"}>
<div class="AllWrapInside clearfix">

  <div class="mainColumn pageMain"><{widgets id="nav"}>  <{main}> </div>
  <div class="sideColumn pageSide"> <{widgets id="sideritems"}> </div>
</div>
<{require file="block/footer.html"}>