Hi,
Would it be correct to say,'the teacher appeared in the class'? My cambridge dictionary says:
Warning: choose the right word!
To talk about a room where students are taught, don't say 'class', say classroom:
The classes had central heating and big windows.
Many Thanks in advance!
Your dictionary is right: The teacher appeared in the classroom. The classrooms had central heating and big windows.
I'll add a further comment on the first example. In my mind, 'appeared' refers to a sudden, unexpected event, as if there was a puff of smoke and the teacher was instantly inside the classroom. Better to say either 'The teacher entered the classroom' or 'The teacher appeared at the classroom door.'