Use had to + verbo para algo que você precisou fazer no passado.
had to + verbo
I had to walk home last night.
She had to take the bus.
Experimente: Woman: Why weren't you at the party last night? Man: I ___ study for a test. Escolha o que o homem diz. (had to / didn't have to / has to) Resposta: had to — Ele perdeu a festa ontem à noite por causa de uma prova, então ele teve que estudar: he had to study.
didn't have to + verbo
Use didn't have to + verbo quando não havia regra, então você podia escolher.
I didn't have to go to school today.
Experimente: Man: Was the form long? Woman: No. I ___ write much. Just my name and address. Escolha o que a mulher diz. (didn't have to / had to / don't have to) Resposta: didn't have to — O formulário só pedia o nome e o endereço dela, então ela não precisou escrever muito: she didn't have to write much.
Perguntas: Did you have to …?
Para perguntar sobre uma regra no passado, diga Did you have to + verbo?
Did you have to wear a uniform at school?
Did he have to pay for the ticket?
Experimente: Man: ___ get up early for the trip? Woman: Yes. The train left at six, so I got up at five. Escolha o que o homem diz. (Did you have to / Do you have to / Did you forget to) Resposta: Did you have to — A viagem já passou e o horário do trem fez ela acordar às cinco, então ele pergunta Did you have to.