英文關鍵字
air
alarm
alert
animation
atom
attention
background
beware
blinking
bomb
caution
computer
danger
dangerous
emergency
error
evacuate
evacuation
explosion
fail
flashing
hazard
illustration
information
licking
light
monitor
nuclear
people
plant
pollution
power
radiation
red
safety
science
screen
security
sign
signal
skull
station
symbol
system
unauthorized
warning
waste