adult
attending
background
blackboard
boy
caucasian
chalkboard
child
class
classroom
coaching
conference
corporate
education
explaining
female
girl
group
happy
indoors
learning
lecture
lesson
listening
meeting
men
modern
people
person
physics
presentation
professional
professor
room
school
seminar
sitting
students
study
studying
teacher
teaching
teaching school
teenage
training
tutor
university
woman
write
young