Used to + infinitive
                    We use used to + infinitive to describe habitual past  actions.
					
							- I used to ride my bicycle to school.
- I didn't use to catch the  bus.
We also use used to + infinitive to describe past states.
					
							- He used to believe in Santa Claus when he was very young.
- She didn't use to have straight hair. Her hair used to be curly. 
We use use to + infinitive with the auxiliary did/didn't in a  question or negative statement.
					
							- A: Did you use to play  basketball?
- B: Yes, I did. / No, I didn't.
- I didn't use to like spinach. Did you?