PRESENT af fir mative ne gative inter r ogative I have to study I don’t have to it Do I have to swim? You have to read a book You don’t have to call her Do you have to study? He has to finish it PAST af fir mative ne gative inter rogative FUTURE affirmative negative interrogative Even Martians have to learn how to use computers A Martian has to know earth language too Have to : to It =isit necessar Has to/have is necessaryy IDon’t/doesn’t don’t havehave to: to It’s not = It’s not necessary