1. My sister ___ mop the floor to get permission to go out with her friends.
a) doesn’t have to
b) has to
Ok! It´s a duty.
Check it! It´s a duty.
2. You ___ touch those plants. They're poisonous.
Ok! It´s dangerous.
Check it! It´s dangerous.
3. There isn’t any milk left. I ___ buy some milk today.
Ok! It´s necessary
Check it! It´s necessary
4. She ___ tidy my room. I'll do it myself.
a) doesn’t have to
b) must
Ok! It´s not necessary.
Check it! It´s not necessary.