upper end of the schedular system

例句：

1. 1.The upper end of the table is where we usually sit.
   桌子的上端是我们通常坐的地方。
2. 2. The upper end of the river is where the rapids are located.
   河流的上端是急流所在的位置。
3. 3.The upper end of the mountain is where the forest begins.
   山的上端是森林开始的地方。