
Regular verb: require - required - required
Simple form | V-ing form | 
| I could require you could require he could require we could require you could require they could require  | I could be requiring you could be requiring he could be requiring we could be requiring you could be requiring they could be requiring  | 
Perfect | V-ing perfect | 
| I could have required you could have required he could have required we could have required you could have required they could have required  | I could have been requiring you could have been requiring he could have been requiring we could have been requiring you could have been requiring they could have been requiring  | 
Simple form | V-ing form | 
| I couldn't require you couldn't require he couldn't require we couldn't require you couldn't require they couldn't require  | I couldn't be requiring you couldn't be requiring he couldn't be requiring we couldn't be requiring you couldn't be requiring they couldn't be requiring  | 
Perfect | V-ing perfect | 
| I couldn't have required you couldn't have required he couldn't have required we couldn't have required you couldn't have required they couldn't have required  | I couldn't have been requiring you couldn't have been requiring he couldn't have been requiring we couldn't have been requiring you couldn't have been requiring they couldn't have been requiring  | 
Simple form | V-ing form | 
| could I require? could you require? could he require? could we require? could you require? could they require?  | could I be requiring? could you be requiring? could he be requiring? could we be requiring? could you be requiring? could they be requiring?  | 
Perfect | V-ing perfect | 
| could I have required? could you have required? could he have required? could we have required? could you have required? could they have required?  | could I have been requiring? could you have been requiring? could he have been requiring? could we have been requiring? could you have been requiring? could they have been requiring?  | 
Simple form | V-ing form | 
| couldn't I require? couldn't you require? couldn't he require? couldn't we require? couldn't you require? couldn't they require?  | couldn't I be requiring? couldn't you be requiring? couldn't he be requiring? couldn't we be requiring? couldn't you be requiring? couldn't they be requiring?  | 
Perfect | V-ing perfect | 
| couldn't I have required? couldn't you have required? couldn't he have required? couldn't we have required? couldn't you have required? couldn't they have required?  | couldn't I have been requiring? couldn't you have been requiring? couldn't he have been requiring? couldn't we have been requiring? couldn't you have been requiring? couldn't they have been requiring?  |