background
black
blackboard
blank
board
brush
chalk
chalkboard
class
classroom
clean
cleaning
clear
college
concept
correction
course
dirty
drawing
duster
education
elementary
empty
erase
eraser
erasing
green
hand
highschool
hold
holding
learn
lesson
message
people
school
space
sponge
student
study
teach
teacher
text
texture
university
white
wipe
write
writing