英文關鍵字
abstract
aluminum
automobile
automotive
background
barrel
black
blue
chrome
circle
circular
closeup
concrete
construction
cutting
engine
engineering
equipment
exhaust
factory
gray
industrial
industry
iron
line
manufacturing
metal
metallic
metalworking
muffler
new
pipe
pipeline
piping
power
production
profile
reflection
saw
sky
stainless
steel
tool
tube
valve
warehouse
water
work
worker
workshop