英文關鍵字
arid
belt
belts
build
carriage
concrete
construct
construction
conveyor
crane
depuration
dig
dirt
dust
earth
elevation
excavator
extraction
factory
falling
flow
grain
gravel
heap
industrial
industry
labor
little
machine
machinery
mason
masonry
material
mining
mixture
mountain
pebble
pebbles
pile
pit
plant
pour
putting
quarry
roller
rotating
sand
sandpit
shot
stone
stones
water
work
working