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.
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