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