English verb conjugation
CAN IMPUGN

Regular verb: impugn - impugned - impugned

Affirmation

Simple form	V-ing form
I can impugn you can impugn he can impugn we can impugn you can impugn they can impugn	I can be impugning you can be impugning he can be impugning we can be impugning you can be impugning they can be impugning
Perfect	V-ing perfect
I can have impugned you can have impugned he can have impugned we can have impugned you can have impugned they can have impugned	I can have been impugning you can have been impugning he can have been impugning we can have been impugning you can have been impugning they can have been impugning

Negation

Simple form	V-ing form
I can't impugn you can't impugn he can't impugn we can't impugn you can't impugn they can't impugn	I can't be impugning you can't be impugning he can't be impugning we can't be impugning you can't be impugning they can't be impugning
Perfect	V-ing perfect
I can't have impugned you can't have impugned he can't have impugned we can't have impugned you can't have impugned they can't have impugned	I can't have been impugning you can't have been impugning he can't have been impugning we can't have been impugning you can't have been impugning they can't have been impugning

Interrogative form

Simple form	V-ing form
can I impugn? can you impugn? can he impugn? can we impugn? can you impugn? can they impugn?	can I be impugning? can you be impugning? can he be impugning? can we be impugning? can you be impugning? can they be impugning?
Perfect	V-ing perfect
can I have impugned? can you have impugned? can he have impugned? can we have impugned? can you have impugned? can they have impugned?	can I have been impugning? can you have been impugning? can he have been impugning? can we have been impugning? can you have been impugning? can they have been impugning?

Interro-negative form

Simple form	V-ing form
can't I impugn? can't you impugn? can't he impugn? can't we impugn? can't you impugn? can't they impugn?	can't I be impugning? can't you be impugning? can't he be impugning? can't we be impugning? can't you be impugning? can't they be impugning?
Perfect	V-ing perfect
can't I have impugned? can't you have impugned? can't he have impugned? can't we have impugned? can't you have impugned? can't they have impugned?	can't I have been impugning? can't you have been impugning? can't he have been impugning? can't we have been impugning? can't you have been impugning? can't they have been impugning?