prolonged illness makes a doctor of a patient ❍ 他本来不懂医道，只是～罢了。He used not to know anything about medicine ,but prolonged illness has made a doctor of him.
久病成医jiu bing cheng yi
prolonged illness makes a patient a doctor
久病成医jiǔ bìnɡ chénɡ yī
长期生病吃药，时间长了，自己也成为医生了。比喻在某一方面经历的时间长了，外行也可以变成内行。prolonged illness makes a doctor of a patient, An old poacher makes the best keeper.