英文關鍵字
adrenaline
bike
biker
championship
cloud
competition
contest
cross
crowd
cup
day
drive
dust
engine
epinephrine
extreme
grass
ground
helmet
hill
human
jump
man
motion
moto
motocross
motor
motorbike
motorcycle
outdoor
outside
pile
pit
quarry
race
ride
slope
smoke
spectator
speed
sport
sportsman
stone
summer
suprarenin
track
trial
two
watch
wheel