Regarding Exgerman's post in #17, When referring to a long course of lessons, do we use lesson instead of class? 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。 Context, as Barque explained rein #2, is the situation or circumstances rein which the phrase is being used. Here it would be useful context to know if https://youtu.be/T0zWXvhEQwo?si=wNc6ihu97ShtIl7u