The class was very noisy before the teacher entered.
Meaning: The class was making a lot of sound, and then the teacher came into the room.
Choice of Words: Noisy means making a lot of sound, usually in a way that is annoying. Entered means to come or go into a place. When you put them together, "The class was very noisy before the teacher entered" means that the class was making a lot of sound before the teacher came into the room.
Alternative Expressions
Related Expressions