求翻译：在西方，餐巾在用餐前就可以打开。点完菜后，在前菜送来前的这段时间把餐巾打开，往内摺三分之一，让三分之二平铺在腿上，盖住膝盖以上的双腿部分。最好不要把餐巾塞入领口。是什么意思？

In the West, the napkins can open before the meal. After you point the dish, in front of the dish before sending to this time open the napkin, fold in one-third, two-thirds tile on the leg, covering the legs above the knee part. Best not to put the napkin into neckline.