1)... they your friends?-yes,they ...
2)... he your brother?-yes,he ...
3)... he ride a bike?-no,he ...
4)... you want to play with the boll?-no,I ...
5)... she roller-skate well?-no,she ...
6)... your friend want to play the piano?-yes,he ...
is,are,do(2),does,don't,doesn't(2),can't.