If we learn in do not understand we should ask a teacher. It should not be kept because of the questions might be, the content is not continuous. It may make us more confused.
If we do not understand in class, we should ask the teacher. Do not keep asking because the content may not be smooth. It may be that we know more than ever.
If we study in the room not, we should ask the teacher. Don't keep asking because may make the content not continuous. It might make us confused than ever before.