1.I used to have a lot of money but I lost it all when my business failed.
2. I quite like classical music now, although I didn't used to be keen on it when I was younger.
3.I used to have interest in my work.
4.My brother used to have his hair cut short when he joined the army.
5.Dennis used to smoke three years ago.
6.My parents used to live in the USA when they were young.
7.Jim used to be my best friend, but we aren't friends any more.
8.When he was younger, my uncle used to be a national swimming champion.
9. I eat ice-cream now, but I didn't used to like eating it when I was a child.
20.When Nam was young, he didn't used to love school. Now he likes school.
21.Ann used to be a secretary for many years, but now she owns her own business.
22.Before Adam got married, he used to go bowling five times a week.
23.When we raised our own chickens, we used to have fresh eggs every morning
24.What did you use to do during summer.
Mình làm "didn't used to" theo đề của bạn nhưng mình nghĩ bạn nên xem lại. Theo mình thì didn't use to mới đúng.