I can umber you can umber he can umber we can umber you can umber they can umber
V-ing form
I can be umbering you can be umbering he can be umbering we can be umbering you can be umbering they can be umbering
Perfect
I can have umbered you can have umbered he can have umbered we can have umbered you can have umbered they can have umbered
V-ing perfect
I can have been umbering you can have been umbering he can have been umbering we can have been umbering you can have been umbering they can have been umbering
Negation
Simple form
I can't umber you can't umber he can't umber we can't umber you can't umber they can't umber
V-ing form
I can't be umbering you can't be umbering he can't be umbering we can't be umbering you can't be umbering they can't be umbering
Perfect
I can't have umbered you can't have umbered he can't have umbered we can't have umbered you can't have umbered they can't have umbered
V-ing perfect
I can't have been umbering you can't have been umbering he can't have been umbering we can't have been umbering you can't have been umbering they can't have been umbering
Interrogative form
Simple form
can I umber? can you umber? can he umber? can we umber? can you umber? can they umber?
V-ing form
can I be umbering? can you be umbering? can he be umbering? can we be umbering? can you be umbering? can they be umbering?
Perfect
can I have umbered? can you have umbered? can he have umbered? can we have umbered? can you have umbered? can they have umbered?
V-ing perfect
can I have been umbering? can you have been umbering? can he have been umbering? can we have been umbering? can you have been umbering? can they have been umbering?
Interro-negative form
Simple form
can't I umber? can't you umber? can't he umber? can't we umber? can't you umber? can't they umber?
V-ing form
can't I be umbering? can't you be umbering? can't he be umbering? can't we be umbering? can't you be umbering? can't they be umbering?
Perfect
can't I have umbered? can't you have umbered? can't he have umbered? can't we have umbered? can't you have umbered? can't they have umbered?
V-ing perfect
can't I have been umbering? can't you have been umbering? can't he have been umbering? can't we have been umbering? can't you have been umbering? can't they have been umbering?