英文關鍵字
activity
alley
back
balance
battery
behind
bicycle
bike
board
boy
car
city
cycle
drive
electric
electrical
entertainment
evening
friendship
fun
futuristic
group
gyroscope
headlights
hoverboard
human
illumination
leisure
machine
modern
motion
motor
night
outdoor
park
people
personal
pleasure
regulations
ride
schoolboy
scooter
security
segway
transport
urban
vehicle
young