There may also be a question of style (formal/conversational). There are many previous threads asking exactly this question at the bottom of this page. 知乎，让每一次点击都充满意义 —— 欢迎来到知乎，发现问题背后的世界。 Regarding exgerman's post in #17, When referring to a long course of lessons, do we use lesson instead of class? But what https://augustqvafj.blogacep.com/39017059/techno-dinge-zu-wissen-bevor-sie-kaufen