英文關鍵字
background
barbed
barbwire
barrier
bird
bleak
border
bound
boundary
chain
cold
crime
criminal
danger
dangerous
doom
escape
fence
forbidden
freedom
grim
guard
guardrail
iron
jail
metal
military
murky
prison
privacy
private
protection
restraint
restriction
safety
secure
security
sharp
sky
spiral
steel
sun
symbol
terror
trees
wall
war
wire