Children ____________tell lies. It's very naughty.
mustn't
I ______ eat too much cake or I'll get fat!.
mustn't
You can borrow my new dress, but you _____ get it dirty.
mustn't
You ________ tidy up now. I'll do it later.
don't have to
John's a millionaire. He ________ go to work.
doesn't have to
All students ________ be on time for class.
must
I ________ do my washing because my mother does it for me.
have to do
You _______tell anyone what I just told you. It's a secret.
mustn't
The museum is free. You ______ pay to get in.
don't have to