英文關鍵字
bright
busy
carriages
construction
craftsperson
cut
cutting
dark
electrodes
engineering
equipment
fabricator
factory
flame
gas
hard
heat
hot
industry
iron
light
manual
manufacturing
mechanical
metal
metalwork
motion
occupation
oxygen
production
protection
protective
safety
slow
sparks
steel
structures
tank
torch
train
valve
welder
welding
work
worker
working