英文關鍵字
action
background
circle
cogs
cogwheel
concept
concepts
connection
cooperation
cooperationconcept
energy
engine
engineering
equipment
gear
gearshift
gearwheels
illustrationandpainting
industrial
industry
invention
iron
machine
machinepart
machinery
machineteeth
macro
mechanical
mechanism
metal
metallic
motion
nobody
part
partof
power
progress
selectivefocus
shiny
silver
steel
teamwork
technical
technology
turn
turning
wheel
white
work
working