英文關鍵字
advice
ahead
alert
arrow
attention
background
beware
black
board
bolt
bright
cables
careful
caution
danger
dangerous
death
electric
electrical
electricity
energy
fence
flash
forbidden
hazard
high
icon
industry
isolated
lightning
metal
notice
power
protect
risk
safety
security
shock
sign
signal
symbol
thunder
triangle
voltage
warning
web
yellow