Complete the sentences with the affirmative ( +), negative ( -) or interrogative ( ?) for of used to.
a) When my grandpa was a kid, he _________ play video games . (-)
b) My mom ________ be a crosswords champion as a teenager. (+)
c) ___________ your father________ play a musical instrument as a child ?
d) Leonardo's parents ______________ like dogs, but now they have a beagle. (-)