Warning, this verb may not exist. Conjugation is given as example.
Affirmation
Simple form
I can fail fail you can fail fail she can fail fail we can fail fail you can fail fail they can fail fail
V-ing form
I can be fail failing you can be fail failing she can be fail failing we can be fail failing you can be fail failing they can be fail failing
Perfect
I can have fail failed you can have fail failed she can have fail failed we can have fail failed you can have fail failed they can have fail failed
V-ing perfect
I can have been fail failing you can have been fail failing she can have been fail failing we can have been fail failing you can have been fail failing they can have been fail failing
Negation
Simple form
I can't fail fail you can't fail fail she can't fail fail we can't fail fail you can't fail fail they can't fail fail
V-ing form
I can't be fail failing you can't be fail failing she can't be fail failing we can't be fail failing you can't be fail failing they can't be fail failing
Perfect
I can't have fail failed you can't have fail failed she can't have fail failed we can't have fail failed you can't have fail failed they can't have fail failed
V-ing perfect
I can't have been fail failing you can't have been fail failing she can't have been fail failing we can't have been fail failing you can't have been fail failing they can't have been fail failing
Interrogative form
Simple form
can I fail fail? can you fail fail? can she fail fail? can we fail fail? can you fail fail? can they fail fail?
V-ing form
can I be fail failing? can you be fail failing? can she be fail failing? can we be fail failing? can you be fail failing? can they be fail failing?
Perfect
can I have fail failed? can you have fail failed? can she have fail failed? can we have fail failed? can you have fail failed? can they have fail failed?
V-ing perfect
can I have been fail failing? can you have been fail failing? can she have been fail failing? can we have been fail failing? can you have been fail failing? can they have been fail failing?
Interro-negative form
Simple form
can't I fail fail? can't you fail fail? can't she fail fail? can't we fail fail? can't you fail fail? can't they fail fail?
V-ing form
can't I be fail failing? can't you be fail failing? can't she be fail failing? can't we be fail failing? can't you be fail failing? can't they be fail failing?
Perfect
can't I have fail failed? can't you have fail failed? can't she have fail failed? can't we have fail failed? can't you have fail failed? can't they have fail failed?
V-ing perfect
can't I have been fail failing? can't you have been fail failing? can't she have been fail failing? can't we have been fail failing? can't you have been fail failing? can't they have been fail failing?