ski
He is good at in-line skating.
in- line skate
surf
ice- skate
He isnt good at snowboarding.
He is good at snowboarding.
snowboard
He isnt good at skiing.
He isnt good at skateboarding.
He is good at ice skating
He isnt good at ice- skating.
He is good at skiing.
He is good at surfing.
skateboard