adult
arguing
audience
back
blur
blurry
business
businessman
casual
ceiling
chairs
classroom
colleagues
communication
conference
congress
discussion
education
event
explaining
group
hand
learning
lecture
light
listening
many
meeting
multimedea
office
participants
people
person
phone
podium
presentation
professor
public
rear
screen
seminar
sit
smart phone
speaker
speaking
talking
team
thouch
training
two
watching
window
woman