Future and Modals : Unit 26, Have to . . .

A.      I have to do something = it is necessary for me to do it or I am obliged to do it :

I/we/you/they  have He/she/it  has

To do . . . To work . . . To go . . . To wear . . .

-          I’ll be late for work tommorow. I have to go to the dentist. (=it is neccessasry
for me to go to the dentist)

-          Sue starts work at 7:00, so she has to get up at 6:00.

-          You have to pass a test before you can get a driver’s license

B.      The Pass (Yesterday / last week, etc.) is had to . . . :

-          I was late for work yesterday. I had to go to the dentist.

-          There was no bus, so we had to walk home.

C.      In questions and negatives we use do/does (present) and did (past) :

-          What time do you have to get up tommorow morning?

-          Does Sue have to work on Saturday?

-          Why did they have to leave the party early?

I don’t have to do (something) = it is not necessary to do it :

-          I’m not working tommorow, so I don’t have to get up early.

-          Mike doesn’t have to work very hard. He has an easy job.

-          We didn’t have to wait very long. The bus came right on time.

D.      Must

You can also use must to say it is necessary to do something :

-          The windows are very dirty. I must clean them. (or  I have to clean them)

-          It’s a fantastic movie. You must see it. (or  You have to see it)

We use have to more often than must, especially in spoken English.