英文關鍵字
construction
cutting
factory
falls
grinder
grinding
industry
iron
machine
manufacturing
metal
motion
production
safety
slow
spark
sparks
steel
welding
work
workshop
英文關鍵字
construction
cutting
factory
falls
grinder
grinding
industry
iron
machine
manufacturing
metal
motion
production
safety
slow
spark
sparks
steel
welding
work
workshop