a course offered (by mail) by a correspondence school
双语例句
He is following a correspondence course in gardening for adults with comparative ease. 他正在上一个相对简单的园艺成人函授课程。
From correspondence courses to tele-classes, distance learning has served the needs of people who cannot physically attend classes. 从函授课程到电视广播课程,远程学习满足了很多由于身体原因不能上学的学习者的需要。