Like the proverbial elephant that is tied to a twig or thin pole. It has been trained not to escape, as the past has taught the elephant that escaping form the pole will bring pain.

如同众所周知的那头被拴在了小细枝或者是细电线杆上的大象，他已经被训练的不再逃跑了，因为过去的事情告诉那头大象，逃离木桩会带来痛苦。