
Verbe régulier : fail -  failed - failed
Traduction française : échouer - échouer à 
Forme simple | Forme en V-ing | 
| I must fail you must fail she must fail we must fail you must fail they must fail  | I must be failing you must be failing she must be failing we must be failing you must be failing they must be failing  | 
Perfect | Perfect en V-ing | 
| I must have failed you must have failed she must have failed we must have failed you must have failed they must have failed  | I must have been failing you must have been failing she must have been failing we must have been failing you must have been failing they must have been failing  | 
Forme simple | Forme en V-ing | 
| I mustn't fail you mustn't fail she mustn't fail we mustn't fail you mustn't fail they mustn't fail  | I mustn't be failing you mustn't be failing she mustn't be failing we mustn't be failing you mustn't be failing they mustn't be failing  | 
Perfect | Perfect en V-ing | 
| I mustn't have failed you mustn't have failed she mustn't have failed we mustn't have failed you mustn't have failed they mustn't have failed  | I mustn't have been failing you mustn't have been failing she mustn't have been failing we mustn't have been failing you mustn't have been failing they mustn't have been failing  | 
Forme simple | Forme en V-ing | 
| must I fail? must you fail? must she fail? must we fail? must you fail? must they fail?  | must I be failing? must you be failing? must she be failing? must we be failing? must you be failing? must they be failing?  | 
Perfect | Perfect en V-ing | 
| must I have failed? must you have failed? must she have failed? must we have failed? must you have failed? must they have failed?  | must I have been failing? must you have been failing? must she have been failing? must we have been failing? must you have been failing? must they have been failing?  | 
Forme simple | Forme en V-ing | 
| mustn't I fail? mustn't you fail? mustn't she fail? mustn't we fail? mustn't you fail? mustn't they fail?  | mustn't I be failing? mustn't you be failing? mustn't she be failing? mustn't we be failing? mustn't you be failing? mustn't they be failing?  | 
Perfect | Perfect en V-ing | 
| mustn't I have failed? mustn't you have failed? mustn't she have failed? mustn't we have failed? mustn't you have failed? mustn't they have failed?  | mustn't I have been failing? mustn't you have been failing? mustn't she have been failing? mustn't we have been failing? mustn't you have been failing? mustn't they have been failing?  |