Information

HAVE TO, DON´T HAVE TO/ MUST/ MUST NOT/ CAN´T + BASE FORM

	Have to, don´t have to
+	She has to get up at 7:00 every day. You have to drive on the left in Japan.
-	We don´t have to wear a uniform at this school. He doesn´t have to work on Saturdays.
?	Do I have to buy a grammar book? Does she have to study tonight?
Don´t contract have or has. I´ve to go. NOT I´ve to go

Use have to + base form to talk about rules and

Obligations, or to say something is necessary.

Use don´t have to + base form to say there is no

Obligation, or something is not necessary.

Use do/does to make questions and negatives

Do I have to go? NOT Have I to go?

	Must/ must not/ can´t
+	All traffic must turn right.
-	Passengers must not leave bags unattended.
-	You can´t bring food into the library.

Use must + base form to talk about rules and obligations.

You must turn off your cell phone before coming into class.

Use can´t/must not + base form to say something is prohibited or to state a rule.

You can´t park here. / You must not park here.

The words can´t  and must not have similar meanings, but

Can´t is more common in speaking. You cab also use cannot.

The verbs must / must not / can´t are the same for all persons.

The verb must is not often used in questions (have to is more common).

Must and have to are very similar, but have to is more common, especially in speaking. Must is often used in official forms, notices, and signs.

Must not and don´t have to completely different meanings. Compare: You must not go= You can´t go. It´s prohibited. You don´t have to go = You can go if you want, but it´s not obligatory/necessary.