pile variable

例句：

1. 1. The children are playing with the blocks on the floor.
   孩子们正在地板上玩积木。
2. 2. The books are piled high in the shelves.
   书被堆在书架上很高。
3. 3. The snow is slowly piling up on the roof.
   雪正在慢慢地堆积在屋顶上。