Complete the sentences with must, mustn’t or don’t / doesn’t have to.

1    I __________________ write to Ella and say thank you for the present.

2    You __________________ tell him about the party. It’s a surprise!

3    Mark __________________ go to work this week. He’s on holiday.

4    We __________________ finish our homework before we go online on a school day. It’s a house rule.

5    You __________________ turn off the computer. I’m going to use it in a minute.

6    People __________________ feed the birds in the park. It’s very bad for them to eat bread.​