Schools seem to often be seeking for superior substitute teachers to add to their rotation. https://spobest.net/%EC%84%A0%EB%B6%88%EC%95%8C%EB%B0%94-%EC%97%AC%EC%84%B1-%EA%B5%AC%EC%9D%B8%EA%B5%AC%EC%A7%81%EC%9D%98-%EC%83%88%EB%A1%9C%EC%9A%B4-%ED%8C%A8%EB%9F%AC%EB%8B%A4%EC%9E%84/
