3四分の一の長さ
20s
adult
attention
back view
boys
caucasian
children
classroom
communication
concentrating
conversation
crop
desk
education
elementary school
girls
guidance
horizontal
incidental people
indoors
kids
knowledge
learning
lesson
listening
man
medium group of people
mentoring
millennials
multiethnic group
one person
panoramic
part of person
preteens
pupils
school
schoolboys
schoolchildren
schoolgirls
selective focus
sitting
standing
students
talking
teacher
teaching
waist up
young adult