60s
academic
age
architect
caucasian
class
classmate
classroom
closeup
college
course
desk
discuss
eco
education
elder
elderly
energy
environment
group
hand
indoor
knowledge
learn
learning
lecture
lesson
man
mature
meeting
old
person
retired
retirement
school
senior
student
study
studying
sustainable
teacher
third
tree
turbine
university
wind
wind turbine
windmill
woman
women