【单选题】For a teacher to facilitate learning effectively in the classroom, he or she must...Which of the following is one of the main roles of the teacher?
A.
Concentrate on teaching to the advantage of the brightest pupils in the classroom .
B.
Do all the talking in the classroom .
C.
Apply strict procedures outlined in his/her teaching/lesson plan.
D.
Have a clear knowledge of who his/her learners are.