RECYCLE! Obligation and prohibition must and have to
When we decide something is an obligation ourselves,
we usually use must. When the obligation is decided
for us by other people, we usually use have to
I must eat more fruit and vegetables.
To enter the marathon, you have to visit the website,
mustn't and don't have to
We use mustn't to say something is prohibited, or to
give very strong advice.
You mustn't eat a lot of sugar.
We use don't have to to say it isn't necessary to do
something
We don't have to take the train next week.
Read the Recycle! box. Then complete the
sentences with the correct form of must,
mustn't have to and don't have to.
1 The trainer tells the marathon runners that they
eat lots of carbohydrates, but that
they
eat fast food
2 The speaker has coeliac disease, so he
buy gluten-free food. But he
go to special shops; he can find it
at the supermarket.
3 The man's doctor warned him that he
start eating more healthily.
4 According to the speaker, people
count how many calories they eat. There are apps to
do it for them.
