Differenciate have to/had to
Please follow the link:
https://www.meritnation.com/cbse/class8/studymaterial/english/english-grammar/tenses/33_449_1571#slide6_the-perfect-tense
https://www.meritnation.com/cbse/class8/studymaterial/english/english-grammar/tenses/33_449_1571#slide6_the-perfect-tense