英文關鍵字
safety
camera
cctv
surveillance
secure
video
protection
technology
crime
privacy
system
observe
digital
monitoring
watch
private
control
screen
electronic
guard
industry
record
information
equipment
looking
view
street
danger
spy
caution
building
alert
film
attention
people
white
hazard
theft
see
robbery
protector
signal
silhouette
display
office
room
background
computer
business
black