They are “helping” verbs that add information to the main verb. She mustn’t chat with strangers. Negative form: + NOT He can’t come today. Questions: subject-verb inversion May I sit here, please? They never change in form: Regular verbs: go, goes, doesn’t go, going … Modals: can / can’t (She can/can’t swim) What are modal verbs?
He can speak French well. ABILITY He can’t be rich, I’m sure. CERTAINTY (-) She can come at any time. POSSIBILITY Can I go out, please? PERMISSION Can you help me, please? REQUEST CAN / CAN’T
Could I borrow your pencil, please? POLITE REQUEST We could go there later. POSSIBILITY I couldn’t read when I was 4 years old. PAST ABILITY COULD / COULDN’T
You must study and work hard. You must have an ID card to enter. OBLIGATION She must be ill. CERTAINTY You mustn’t fight with your brother. You mustn’t drive without a license. PROHIBITION MUST / MUSTN’T
May I have another one, please? POLITE REQUEST China may become a major economic power. POSSIBILITY MAY / MAY NOT
You should eat healthy. You shouldn’t spend so many hours on the computer. Should I call my mother? ADVICE SHOULD / SHOULDN’T