英文關鍵字
asphalt
background
blade
bulldozer
business
caution
constructing
construction
dirt
earth
engine
engineering
equipment
excavator
grader
grading
gravel
ground
heavy
highway
hydraulics
industrial
industry
large
machine
machines
maintenance
metal
motor
operator
power
road
site
track
tractor
transportation
truck
vehicle
wheel
work
worker
yellow