英文關鍵字
address
alert
amp
amplification
amplifier
announce
announcement
attention
audio
blue
broadcast
bunch
commentate
communication
cone
danger
electric
electricity
information
loud
loudspeaker
megafon
megaphone
music
old
outdoor
pole
post
power
public
rusty
shout
siren
sky
sound
speak
speaker
station
system
talk
tree
trumpet
vintage
voice
volume
warning
white
wire
wiring