DO YOU SAY THIS: "THE ROOM IS PLENTY OF PEOPLE"?
If you do, then don't worry because about 75% of our students say the same. The correct version of this sentence is: "The room is full with people". The word "plenty" is used in a different context and means "más que suficiente".
So, imagine that you are invited to a dinner party and the host starts to put food on your plate, at that point you could say "That is plenty! Thank you". Another context would be if someone asks you if there are enough chairs in the meeting room. You could say at that point: "Yes, there are plenty of chairs".
Hope that helps!
Soy el director de Daniel Smith + Partners. Tengo más de 10 años de experiencia enseñando inglés a españoles.