
Regular verb: interest - interested - interested
Simple form | V-ing form | 
| I must interest you must interest she must interest we must interest you must interest they must interest  | I must be interesting you must be interesting she must be interesting we must be interesting you must be interesting they must be interesting  | 
Perfect | V-ing perfect | 
| I must have interested you must have interested she must have interested we must have interested you must have interested they must have interested  | I must have been interesting you must have been interesting she must have been interesting we must have been interesting you must have been interesting they must have been interesting  | 
Simple form | V-ing form | 
| I mustn't interest you mustn't interest she mustn't interest we mustn't interest you mustn't interest they mustn't interest  | I mustn't be interesting you mustn't be interesting she mustn't be interesting we mustn't be interesting you mustn't be interesting they mustn't be interesting  | 
Perfect | V-ing perfect | 
| I mustn't have interested you mustn't have interested she mustn't have interested we mustn't have interested you mustn't have interested they mustn't have interested  | I mustn't have been interesting you mustn't have been interesting she mustn't have been interesting we mustn't have been interesting you mustn't have been interesting they mustn't have been interesting  | 
Simple form | V-ing form | 
| must I interest? must you interest? must she interest? must we interest? must you interest? must they interest?  | must I be interesting? must you be interesting? must she be interesting? must we be interesting? must you be interesting? must they be interesting?  | 
Perfect | V-ing perfect | 
| must I have interested? must you have interested? must she have interested? must we have interested? must you have interested? must they have interested?  | must I have been interesting? must you have been interesting? must she have been interesting? must we have been interesting? must you have been interesting? must they have been interesting?  | 
Simple form | V-ing form | 
| mustn't I interest? mustn't you interest? mustn't she interest? mustn't we interest? mustn't you interest? mustn't they interest?  | mustn't I be interesting? mustn't you be interesting? mustn't she be interesting? mustn't we be interesting? mustn't you be interesting? mustn't they be interesting?  | 
Perfect | V-ing perfect | 
| mustn't I have interested? mustn't you have interested? mustn't she have interested? mustn't we have interested? mustn't you have interested? mustn't they have interested?  | mustn't I have been interesting? mustn't you have been interesting? mustn't she have been interesting? mustn't we have been interesting? mustn't you have been interesting? mustn't they have been interesting?  |