英文關鍵字
belt
bulldozer
business
cement
cobblestone
construction
conveyor
crisis
crushed
dig
dump
earth
engineering
equipment
extraction
factory
framework
gallop
gravel
heap
heaps
industrial
industry
iron
large
lorry
macadam
machine
machinery
manufacturing
material
materials
mine
mineral
mountain
outside
piles
plant
processing
quarry
rocas
sandpit
stack
steel
structures
technology
tracks
transport
tyre
working