英文關鍵字
20s
academic
adult
attentively
book
campus
casual
caucasian
cheerful
class
classmates
clothing
college
communication
concentrated
concentrating
conversation
discussion
education
female
finger
five
focused
folder
frowning
happy
higher
interacting
knowledge
lesson
listening
male
man
mixedrace
notebook
paper
people
pointing
school
serious
smiling
speaking
standing
stern
student
talking
thoughtful
university
unsmiling
woman
young