
Regular verb: fault - faulted - faulted
Simple form | V-ing form | 
| I must fault you must fault he must fault we must fault you must fault they must fault  | I must be faulting you must be faulting he must be faulting we must be faulting you must be faulting they must be faulting  | 
Perfect | V-ing perfect | 
| I must have faulted you must have faulted he must have faulted we must have faulted you must have faulted they must have faulted  | I must have been faulting you must have been faulting he must have been faulting we must have been faulting you must have been faulting they must have been faulting  | 
Simple form | V-ing form | 
| I mustn't fault you mustn't fault he mustn't fault we mustn't fault you mustn't fault they mustn't fault  | I mustn't be faulting you mustn't be faulting he mustn't be faulting we mustn't be faulting you mustn't be faulting they mustn't be faulting  | 
Perfect | V-ing perfect | 
| I mustn't have faulted you mustn't have faulted he mustn't have faulted we mustn't have faulted you mustn't have faulted they mustn't have faulted  | I mustn't have been faulting you mustn't have been faulting he mustn't have been faulting we mustn't have been faulting you mustn't have been faulting they mustn't have been faulting  | 
Simple form | V-ing form | 
| must I fault? must you fault? must he fault? must we fault? must you fault? must they fault?  | must I be faulting? must you be faulting? must he be faulting? must we be faulting? must you be faulting? must they be faulting?  | 
Perfect | V-ing perfect | 
| must I have faulted? must you have faulted? must he have faulted? must we have faulted? must you have faulted? must they have faulted?  | must I have been faulting? must you have been faulting? must he have been faulting? must we have been faulting? must you have been faulting? must they have been faulting?  | 
Simple form | V-ing form | 
| mustn't I fault? mustn't you fault? mustn't he fault? mustn't we fault? mustn't you fault? mustn't they fault?  | mustn't I be faulting? mustn't you be faulting? mustn't he be faulting? mustn't we be faulting? mustn't you be faulting? mustn't they be faulting?  | 
Perfect | V-ing perfect | 
| mustn't I have faulted? mustn't you have faulted? mustn't he have faulted? mustn't we have faulted? mustn't you have faulted? mustn't they have faulted?  | mustn't I have been faulting? mustn't you have been faulting? mustn't he have been faulting? mustn't we have been faulting? mustn't you have been faulting? mustn't they have been faulting?  |