1 Must and have to
a This is a rule in a British Rail leaflet about a Young Person's Railcard.
You must buy your ticket before starting your journey, unless you join the train at
a station where ticket purchase facilities are not available.
Now look at this conversation.
Abigail: There isn't much time to spare. You'd better buy your ticket on the train.
Phil: I can't do that. I want to use this railcard. I have to buy the ticket before
I get on.
12 MODAL VERBS PAGE l16
When we talk about necessity in the present or the near future, we can use either
must or have (got) to. But there is a difference in meaning. We normally use must
when the speaker feels the necessity and have to when the necessity is outside the
speaker.
You must buy your ticket before starting your journey.
I have to buy the ticket before I get on the train.
The leaflet uses must because the rule is made by British Rail, and they are the
authority. Phil uses have to because the rule is not his, and the necessity results
from the situation.
You must... is a way of ordering someone to do something. You have to... is a way
of telling them what is necessary in the situation.
You must fill in a form. (I'm telling you.)
You have to fill in a form. (That's the rule.)
I must go on a diet. I'm getting overweight.
I have to go on a diet. The doctor has told me to