
Verbo regular: keen - keened - keened
Forma simple | Forma con V-ing | 
| I must keen you must keen she must keen we must keen you must keen they must keen  | I must be keening you must be keening she must be keening we must be keening you must be keening they must be keening  | 
Perfecto | Perfecto con V-ing | 
| I must have keened you must have keened she must have keened we must have keened you must have keened they must have keened  | I must have been keening you must have been keening she must have been keening we must have been keening you must have been keening they must have been keening  | 
Forma simple | Forma con V-ing | 
| I mustn't keen you mustn't keen she mustn't keen we mustn't keen you mustn't keen they mustn't keen  | I mustn't be keening you mustn't be keening she mustn't be keening we mustn't be keening you mustn't be keening they mustn't be keening  | 
Perfecto | Perfecto con V-ing | 
| I mustn't have keened you mustn't have keened she mustn't have keened we mustn't have keened you mustn't have keened they mustn't have keened  | I mustn't have been keening you mustn't have been keening she mustn't have been keening we mustn't have been keening you mustn't have been keening they mustn't have been keening  | 
Forma simple | Forma con V-ing | 
| must I keen? must you keen? must she keen? must we keen? must you keen? must they keen?  | must I be keening? must you be keening? must she be keening? must we be keening? must you be keening? must they be keening?  | 
Perfecto | Perfecto con V-ing | 
| must I have keened? must you have keened? must she have keened? must we have keened? must you have keened? must they have keened?  | must I have been keening? must you have been keening? must she have been keening? must we have been keening? must you have been keening? must they have been keening?  | 
Forma simple | Forma con V-ing | 
| mustn't I keen? mustn't you keen? mustn't she keen? mustn't we keen? mustn't you keen? mustn't they keen?  | mustn't I be keening? mustn't you be keening? mustn't she be keening? mustn't we be keening? mustn't you be keening? mustn't they be keening?  | 
Perfecto | Perfecto con V-ing | 
| mustn't I have keened? mustn't you have keened? mustn't she have keened? mustn't we have keened? mustn't you have keened? mustn't they have keened?  | mustn't I have been keening? mustn't you have been keening? mustn't she have been keening? mustn't we have been keening? mustn't you have been keening? mustn't they have been keening?  |