I can require you can require she can require we can require you can require they can require
V-ing form
I can be requiring you can be requiring she can be requiring we can be requiring you can be requiring they can be requiring
Perfect
I can have required you can have required she can have required we can have required you can have required they can have required
V-ing perfect
I can have been requiring you can have been requiring she can have been requiring we can have been requiring you can have been requiring they can have been requiring
Negation
Simple form
I can't require you can't require she can't require we can't require you can't require they can't require
V-ing form
I can't be requiring you can't be requiring she can't be requiring we can't be requiring you can't be requiring they can't be requiring
Perfect
I can't have required you can't have required she can't have required we can't have required you can't have required they can't have required
V-ing perfect
I can't have been requiring you can't have been requiring she can't have been requiring we can't have been requiring you can't have been requiring they can't have been requiring
Interrogative form
Simple form
can I require? can you require? can she require? can we require? can you require? can they require?
V-ing form
can I be requiring? can you be requiring? can she be requiring? can we be requiring? can you be requiring? can they be requiring?
Perfect
can I have required? can you have required? can she have required? can we have required? can you have required? can they have required?
V-ing perfect
can I have been requiring? can you have been requiring? can she have been requiring? can we have been requiring? can you have been requiring? can they have been requiring?
Interro-negative form
Simple form
can't I require? can't you require? can't she require? can't we require? can't you require? can't they require?
V-ing form
can't I be requiring? can't you be requiring? can't she be requiring? can't we be requiring? can't you be requiring? can't they be requiring?
Perfect
can't I have required? can't you have required? can't she have required? can't we have required? can't you have required? can't they have required?
V-ing perfect
can't I have been requiring? can't you have been requiring? can't she have been requiring? can't we have been requiring? can't you have been requiring? can't they have been requiring?