英文關鍵字
assembly
big
board
business
chrome
construction
cut
diameter
engineering
equipment
fasteners
fittings
gas
gasoline
generation
heavy
industry
iron
line
machine
manufacturing
material
mechanic
metal
mill
modern
natural
new
oil
parts
petroleum
pipe
pipeline
press
pressure
protective
pump
safety
sell
sharpen
shavings
stack
technology
tube
valve
work
worker