I can ail you can ail he can ail we can ail you can ail they can ail
V-ing form
I can be ailing you can be ailing he can be ailing we can be ailing you can be ailing they can be ailing
Perfect
I can have ailed you can have ailed he can have ailed we can have ailed you can have ailed they can have ailed
V-ing perfect
I can have been ailing you can have been ailing he can have been ailing we can have been ailing you can have been ailing they can have been ailing
Negation
Simple form
I cannot ail you cannot ail he cannot ail we cannot ail you cannot ail they cannot ail
V-ing form
I cannot be ailing you cannot be ailing he cannot be ailing we cannot be ailing you cannot be ailing they cannot be ailing
Perfect
I cannot have ailed you cannot have ailed he cannot have ailed we cannot have ailed you cannot have ailed they cannot have ailed
V-ing perfect
I cannot have been ailing you cannot have been ailing he cannot have been ailing we cannot have been ailing you cannot have been ailing they cannot have been ailing
Interrogative form
Simple form
can I ail? can you ail? can he ail? can we ail? can you ail? can they ail?
V-ing form
can I be ailing? can you be ailing? can he be ailing? can we be ailing? can you be ailing? can they be ailing?
Perfect
can I have ailed? can you have ailed? can he have ailed? can we have ailed? can you have ailed? can they have ailed?
V-ing perfect
can I have been ailing? can you have been ailing? can he have been ailing? can we have been ailing? can you have been ailing? can they have been ailing?
Interro-negative form
Simple form
can I not ail? can you not ail? can he not ail? can we not ail? can you not ail? can they not ail?
V-ing form
can I not be ailing? can you not be ailing? can he not be ailing? can we not be ailing? can you not be ailing? can they not be ailing?
Perfect
can I not have ailed? can you not have ailed? can he not have ailed? can we not have ailed? can you not have ailed? can they not have ailed?
V-ing perfect
can I not have been ailing? can you not have been ailing? can he not have been ailing? can we not have been ailing? can you not have been ailing? can they not have been ailing?