英文關鍵字
abstract
aged
agricultural
agriculture
background
closeup
cogs
cogwheel
concept
crawler
dark
detail
dirty
engine
engineering
equipment
factory
farm
fashioned
gear
green
grunge
heavy
industrial
industry
iron
machine
machinery
mechanical
mechanism
metal
metallic
nobody
objects
obsolete
old
part
photo
power
retro
rotor
rural
rusty
scene
technical
technology
tractor
transportation
vintage
wheel