黔驴技穷

In ancient times there were no donkeys in Guizhou province. Somebody brought a donkey from somewhere and tied it to a tree at the foot of a mountain. A tiger saw the donkey, and thought that it must be a fearsome（可怕的） monster. It hide behind a tree and spied on the donkey. When the donkey brayed¹（叫） , the tiger was frightened, thinking that the donkey was about to devour²（吞食，毁灭） it. After a while, seeing that the donkey had not moved, the tiger approached it and teased it. The donkey became angry, and kicked the tiger. The tiger thought to itself: "Its then all it is capable of?" It then jumped on the donkey and ate it.

This idiom is used to mean that one has exhauseted one's skills.