(+) S + used to + Vnt
Ex: He used to play robots.
She used to play dolls.
(-) S + did + not + use to + Vnt
Ex: They didn't use to be friendly.
She did not use to like him.
(?) (Wh) + did + S + use to + Vnt?
Ex: Who did he use to love?
Which toys did your friends use to play?