“江山易改，本性难移”，汉语成语，意思是人的本性的改变比江山的变迁还要难。形容人的内在秉性难以改变，与英文习语“a leopard can't change its spots或a tiger cannot change its stripes”意思相近，表示“One can't change one's essential nature”。
- 我们分手后，他回来找我，试图让我相信他已经变了。但是我知道江山易改本性难移。
After our breakup, he came crawling back, trying to convince me that he'd changed, but I know that a leopard can't change its spots. - 他一定还会挂科的，毕竟江山易改本性难移。
He is bound to fail the exam again, a leopard cannot change his spots after all.
