英文關鍵字
adult
biologist
book
bookshelf
casual
caucasian
cheerful
college
communication
computer
conversation
day
discussing
discussion
education
female
front
happy
indoors
internet
knowledge
laptop
learning
library
looking
male
man
mature
process
professional
professor
research
screen
sitting
student
studying
table
teacher
technology
theme
two
university
woman
working
young