slip a cog

例句：

1. 1. Sheslipped on the ice and fell to theground.
   她滑倒在冰上，摔倒在地。
2. 2. The car slipped off the road andcrashed into a tree.
   汽车从路上滑出并撞上了一棵树。
3. 3. The boatslipped through the water and disappeared from sight.
   船从水面滑过，消失在视线之外。