That's life unfortunately. As a dated BE speaker I would not use class, I would use lesson. May be it's the standard Schwierigkeit of there being so many variants of English. 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。 edit: this seems to be the consensus over at the Swedish section of WordReference back https://seitensprung36035.bloguetechno.com/das-5-sekunden-trick-für-chill-68887298