英文關鍵字
area
arrow
attention
beware
board
caution
charge
danger
dangerous
death
electric
electrical
electricity
emblem
energy
fence
hazard
hazardous
industrial
industry
lightning
pictogram
power
powerlines
precaution
protect
railway
restricted
risk
safety
security
shock
sign
signal
signboard
sunset
supply
symbol
technology
tension
threat
trains
transformer
triangle
volt
voltage
warning
wired
yellow
zone