I can mail you can mail he can mail we can mail you can mail they can mail
V-ing form
I can be mailing you can be mailing he can be mailing we can be mailing you can be mailing they can be mailing
Perfect
I can have mailed you can have mailed he can have mailed we can have mailed you can have mailed they can have mailed
V-ing perfect
I can have been mailing you can have been mailing he can have been mailing we can have been mailing you can have been mailing they can have been mailing
Negation
Simple form
I can't mail you can't mail he can't mail we can't mail you can't mail they can't mail
V-ing form
I can't be mailing you can't be mailing he can't be mailing we can't be mailing you can't be mailing they can't be mailing
Perfect
I can't have mailed you can't have mailed he can't have mailed we can't have mailed you can't have mailed they can't have mailed
V-ing perfect
I can't have been mailing you can't have been mailing he can't have been mailing we can't have been mailing you can't have been mailing they can't have been mailing
Interrogative form
Simple form
can I mail? can you mail? can he mail? can we mail? can you mail? can they mail?
V-ing form
can I be mailing? can you be mailing? can he be mailing? can we be mailing? can you be mailing? can they be mailing?
Perfect
can I have mailed? can you have mailed? can he have mailed? can we have mailed? can you have mailed? can they have mailed?
V-ing perfect
can I have been mailing? can you have been mailing? can he have been mailing? can we have been mailing? can you have been mailing? can they have been mailing?
Interro-negative form
Simple form
can't I mail? can't you mail? can't he mail? can't we mail? can't you mail? can't they mail?
V-ing form
can't I be mailing? can't you be mailing? can't he be mailing? can't we be mailing? can't you be mailing? can't they be mailing?
Perfect
can't I have mailed? can't you have mailed? can't he have mailed? can't we have mailed? can't you have mailed? can't they have mailed?
V-ing perfect
can't I have been mailing? can't you have been mailing? can't he have been mailing? can't we have been mailing? can't you have been mailing? can't they have been mailing?