thread slipping

例句：

1. 1.The old clock's hands were slipping on the wall.
   旧钟表的指针在墙上滑脱。
2. 2. The child was sliding down the hill when he slipped and fell.
   孩子在滑下山坡时滑脱并摔倒了。
3. 3.The rope was slipping from her hand as she tried to hold it.
   她试图抓住绳子，但绳子从她的手中滑脱了。