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 cannot impugn you cannot impugn he cannot impugn we cannot impugn you cannot impugn they cannot impugn	I cannot be impugning you cannot be impugning he cannot be impugning we cannot be impugning you cannot be impugning they cannot be impugning
Perfect	V-ing perfect
I cannot have impugned you cannot have impugned he cannot have impugned we cannot have impugned you cannot have impugned they cannot have impugned	I cannot have been impugning you cannot have been impugning he cannot have been impugning we cannot have been impugning you cannot have been impugning they cannot 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 I not impugn? can you not impugn? can he not impugn? can we not impugn? can you not impugn? can they not impugn?	can I not be impugning? can you not be impugning? can he not be impugning? can we not be impugning? can you not be impugning? can they not be impugning?
Perfect	V-ing perfect
can I not have impugned? can you not have impugned? can he not have impugned? can we not have impugned? can you not have impugned? can they not have impugned?	can I not have been impugning? can you not have been impugning? can he not have been impugning? can we not have been impugning? can you not have been impugning? can they not have been impugning?