apical pad

例句：

1. 1. The apex of the mountainis covered with snow.
   山顶被雪覆盖。
2. 2.The apex of the roof iswhere the tiles meet.
   屋顶的顶端是瓷砖相接的地方。
3. 3. The apex ofthe arch was made from stone.
   拱门的最高点是用石头制成的。