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 | |
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. |
