Direct speech: He said, "If the flood gets worse we must leave the house."
Indirect speech (book answer): He said that if the flood got worse they would have to leave the house.
I think there should be must/had to instead of would have to, because I read a rule saying we change must into must/had to when we change direct speech into indirect speech.
Correct me if I am wrong?
Best Answer
I think the book answer is right. We really can't use "must" to mean "have to" in the past. So we switch to "have to." Then, since it's reported speech, we have to use the conditional "would have to."
I wish books didn't teach "must" in this context, by the way, because it's much rarer than "have to." Nobody would ever say "if the flood gets worse we must leave the house." We'd say "if the flood gets worse, we have to leave the house."