must
part of speech
verb (must — modal, no other forms; must not, mustn't; must have); noun (a must — informal)
meaning for a pupil
1) Must means something has to happen; it is needed or it is a rule: «You must wear shoes.» tree →
2) Must also means you are almost sure something is true: «You must be tired.» tree →
3) «Must not» means it is not allowed. tree →
4) A must is something you really should do or have: «Sunscreen is a must.» tree →
5) «Must have» + past form means you are almost sure about the past: «It must have rained.» tree →
6) (casual) «Gotta» and «have to» are the everyday words for must: «gotta go», «I've gotta save 30 more». tree →
7) (rough, sarcastic) «Must you?» means stop it, you are annoying; «if you must» means I don't like it, but fine. tree →
8) (formal) «Shall», «is required to», «is obliged to» and «it is necessary that» are the stiff words: «Each candidate shall provide…» tree →
sense in the lessons
a need or rule in the story: how many must be bought, how far one must go, how much more one must save; in safety rules «you must» and «you must not»; in logic «it must be» shows a sure conclusion; in casual talk «gotta», «have to», «need to»; in the exam voice «is required to», «shall»; phrases «must have», «a must», «must-see», «if you must»
examples
- How many more pages must she read? tree →
- He must save 30 dollars more. tree →
- Each box must hold 6 eggs. tree →
- How many buses must they rent? tree →
- You must not swim without a grown-up. tree →
- Everyone must wear a helmet on a bike. tree →
- The grass is wet, so it must have rained. tree →
- You must be hungry after the long walk. tree →
- gotta get 30 more bucks before sat, how many weeks at 5 a week (casual) tree →
- Must you bang that drum? Give it a rest. (rough) tree →
- That film is a must-see. tree →
- Each vehicle is required to accommodate 40 passengers; determine the minimum number of vehicles necessitated for 130 persons. (formal exam) tree →
- I must know more of them." tree →
note
«Must still» or «more … must» often asks for what is left: need − have. «How many buses must they rent» often needs rounding up after dividing. Trap: when you divide, do not drop the part left over if one more bus or box is needed. Must has no -s and no past form: «she must», not «she musts»; use «had to» for the past. «Must not» (forbidden) differs from «don't have to» (not needed). «Gotta» = have got to (casual, spoken only). Formal «is required to» and «shall» = must. «Must be» can be a guess, not a rule: «you must be Tom» means I think you are Tom.
In the corpora
- A debit card spends money already in the account; a credit card borrows money that must be paid back later.
- Parents often make a shortlist of names, and the name must be registered officially within a few weeks of the birth.
- "When the fun stops, stop" is a warning betting adverts must include, because gambling can become an addiction.
- A siren and flashing blue lights mean police are rushing to an emergency, and other drivers must pull over to let them through.
- A speed camera photographs cars going over the limit, and the driver must pay a fine and may get points on their licence.
Trees and pragmatics
Every meaning and example of «must» parsed by Mova, each sentence with its dependency tree and frames.