stack push down

例句：

1. 1. The boxes are stacked neatly in the warehouse.
   箱子整齐地堆放在仓库里。
2. 2. The books were stacked on the shelves.
   书被堆放在书架上。
3. 3. The workers stacked the crates to load onto the truck.
   工人们把纸箱堆放起来，准备装车。