英文關鍵字
barge
boat
bridge
building
channel
clean
cleanup
clearance
construction
crane
deepen
deepening
depth
dig
digging
dirt
dirty
dredge
dredger
dredging
ecology
environment
environmental
equipment
excavating
excavation
excavator
heavy
hydraulic
industrial
industry
iron
ladle
landscape
machine
maintenance
mechanism
nature
recycling
river
ship
sky
techniques
technology
transport
water
weather
widening
work