Respuestas
Respuesta:
1. You mustn't tell lies. It's very naughty.
2. You don't have to come with me if you don't want to.
3. The British Museum is free. You don't have to pay.
4. Jimmy is very ill. He mustn't get out of bed.
5. Tell your children they mustn't pick the flowers in my garden!
6. I have the day off tomorrow, so I don't have to get up early!
7. Vanessa is very rich. She don't have to go to work.
8. Sh! The baby's assleep! You mustn't wake her!
Explicación:
Cuando negamos la expresión have to, tenemos doesn't / don't have to, que expresa una falta de obligación. No tienes que hacerlo, pero puedes si quieres.
I don't have to get up early tomorrow.
She doesn't have to pay the phone bill this week.
They don't have to study hard for their exams.
Mustn't, en cambio, habla de prohibición: algo que no debes hacer. Así, es muy diferente a don't have to, que habla de falta de obligación.
You musn't call me after dinner. I'll be asleep.
I mustn't go anywhere. I have to look after the baby.
You mustn't tell Pepe what happened. You might hurt his feelings.