機器
activity
belt
business
cobblestone
concrete
construction
conveyor
crisis
crushed
dig
dump
earth
engineering
equipment
extraction
factory
gravel
heap
heavy
hole
industrial
industry
iron
large
lorry
machinery
manufacturing
material
metal
mine
mineral
mountain
outside
pouring
production
quarry
quarrying
rock
sand
stack
steel
stone
technology
transportation
work
working