機器
environmental
action
big
black
brown
bucket
carbon
coal
digger
digging
dust
earth
ecology
energy
enormous
environment
excavation
excavator
exploitation
fossil
fuel
giant
gigantic
ground
heap
heavy
industrial
industry
large
loader
metal
method
mine
move
power
scoop
steel
strip
surface
technology
the nature
utilities
vehicle
wheel
work