
Irregular verb: undergo - underwent - undergone
Simple form | V-ing form | 
| I must undergo you must undergo she must undergo we must undergo you must undergo they must undergo  | I must be undergoing you must be undergoing she must be undergoing we must be undergoing you must be undergoing they must be undergoing  | 
Perfect | V-ing perfect | 
| I must have undergone you must have undergone she must have undergone we must have undergone you must have undergone they must have undergone  | I must have been undergoing you must have been undergoing she must have been undergoing we must have been undergoing you must have been undergoing they must have been undergoing  | 
Simple form | V-ing form | 
| I mustn't undergo you mustn't undergo she mustn't undergo we mustn't undergo you mustn't undergo they mustn't undergo  | I mustn't be undergoing you mustn't be undergoing she mustn't be undergoing we mustn't be undergoing you mustn't be undergoing they mustn't be undergoing  | 
Perfect | V-ing perfect | 
| I mustn't have undergone you mustn't have undergone she mustn't have undergone we mustn't have undergone you mustn't have undergone they mustn't have undergone  | I mustn't have been undergoing you mustn't have been undergoing she mustn't have been undergoing we mustn't have been undergoing you mustn't have been undergoing they mustn't have been undergoing  | 
Simple form | V-ing form | 
| must I undergo? must you undergo? must she undergo? must we undergo? must you undergo? must they undergo?  | must I be undergoing? must you be undergoing? must she be undergoing? must we be undergoing? must you be undergoing? must they be undergoing?  | 
Perfect | V-ing perfect | 
| must I have undergone? must you have undergone? must she have undergone? must we have undergone? must you have undergone? must they have undergone?  | must I have been undergoing? must you have been undergoing? must she have been undergoing? must we have been undergoing? must you have been undergoing? must they have been undergoing?  | 
Simple form | V-ing form | 
| mustn't I undergo? mustn't you undergo? mustn't she undergo? mustn't we undergo? mustn't you undergo? mustn't they undergo?  | mustn't I be undergoing? mustn't you be undergoing? mustn't she be undergoing? mustn't we be undergoing? mustn't you be undergoing? mustn't they be undergoing?  | 
Perfect | V-ing perfect | 
| mustn't I have undergone? mustn't you have undergone? mustn't she have undergone? mustn't we have undergone? mustn't you have undergone? mustn't they have undergone?  | mustn't I have been undergoing? mustn't you have been undergoing? mustn't she have been undergoing? mustn't we have been undergoing? mustn't you have been undergoing? mustn't they have been undergoing?  |