下端背面

例句：

1. 1. The book is lying open on the table.
   书摊开着放在桌子上。
2. 2. She turned around to see who was behind her.
   她转过身去看看是谁在她后面。
3. 3. He sat down on the back of the couch.
   他坐在沙发的后背上。