I could require you could require he could require we could require you could require they could require
V-ing form
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
I could have required you could have required he could have required we could have required you could have required they could have required
V-ing perfect
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
Negation
Simple form
I could not require you could not require he could not require we could not require you could not require they could not require
V-ing form
I could not be requiring you could not be requiring he could not be requiring we could not be requiring you could not be requiring they could not be requiring
Perfect
I could not have required you could not have required he could not have required we could not have required you could not have required they could not have required
V-ing perfect
I could not have been requiring you could not have been requiring he could not have been requiring we could not have been requiring you could not have been requiring they could not have been requiring
Interrogative form
Simple form
could I require? could you require? could he require? could we require? could you require? could they require?
V-ing form
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
could I have required? could you have required? could he have required? could we have required? could you have required? could they have required?
V-ing perfect
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?
Interro-negative form
Simple form
could I not require? could you not require? could he not require? could we not require? could you not require? could they not require?
V-ing form
could I not be requiring? could you not be requiring? could he not be requiring? could we not be requiring? could you not be requiring? could they not be requiring?
Perfect
could I not have required? could you not have required? could he not have required? could we not have required? could you not have required? could they not have required?
V-ing perfect
could I not have been requiring? could you not have been requiring? could he not have been requiring? could we not have been requiring? could you not have been requiring? could they not have been requiring?