| Modal verbs and their negatives | ||
| positive | negative | |
|
must (used for a personal opinion) He must be crazy. |
can't He can't be crazy. |
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|
must / have to / has to (used for obligation) You must be there at 8 o'clock. You have to be there at 8 o'clock. |
don't have to / needn't = something is not necessary You don't have to be there at 8 o'clock. You needn't be there at 8 o'clock. |
|
|
can (used for ability) I can play the guitar. |
can't / cannot I can't play the guitar. |
|
|
can (used for possibility) You can smoke here. |
can't / cannot / mustn't You can't smoke here. You mustn't smoke here. |
|
Better English
