英文關鍵字
noise
ear
person
protection
safety
earplug
loud
equipment
quiet
sound
silence
male
protective
care
man
hearing
prevention
people
hear
inserting
noisy
hand
plug
health
caucasian
adult
reduce
soft
decibel
calm
human
home
comfortable
happy
sleep
industry
earplugs
putting
hygiene
wearing
filter
reusable
reduction
object
muffled
bed
pollution
muted
good
quietness