academic
adult
background
blackboard
book
caucasian
chalkboard
class
classroom
college
desk
education
expertise
explain
information
knowledge
learn
lecture
lesson
male
man
mature
middleaged
occupation
person
point
pointer
professor
pupil
read
school
science
seminar
senior
show
showing
smart
speaker
standing
student
study
studying
suit
task
teach
teacher
teaching
textbook
university
work