Resposta :
a) I can play the guitar, but I can't play the piano
b) Janet could speak English, but she couldn't speak Portuguese
c) You can swim in the pool, but you can't swim in the river
d) My brother could ride a bike, but he couldn't rollerblade
e) The boys can play volleyball, but they can't play football
f) My mother could drive a car, but she couldn't drive a motorcicle