1 A general question to the sentence . He used to play football when he was a child.
a) did he use to play football when he was a child ?
b) used he to play  football when he was a child ?
c) did he used to play football when he was a child ?
d) what did he use to play when he was a child ?
e) he used to play football when he was a child , didnt he
2)