
Modal auxiliary can - could
Present | Present continuous | Preterite | Preterite continuous | 
|  cannot I? cannot you? cannot she? cannot we? cannot you? cannot they?  | - |  couldnot I? couldnot you? couldnot she? couldnot we? couldnot you? couldnot they?  | - | 
Present perfect | Present perfect continuous | Pluperfect | Pluperfect continuous | 
| - | - | - | - | 
Future | Future continuous | Future perfect | Future perfect continuous | 
| - | - | - | - | 
Present | Present continuous | Past | Past continuous | 
| - | - | - | - | 
Infinitive | Imperative | 
Infinitive | Imperative | ||
| - | - | 
Present | Past | ||
| - | - |