English verb conjugation
COULD IMPUGN

Regular verb: impugn - impugned - impugned

Affirmation

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

Negation

Simple form	V-ing form
I could not impugn you could not impugn he could not impugn we could not impugn you could not impugn they could not impugn	I could not be impugning you could not be impugning he could not be impugning we could not be impugning you could not be impugning they could not be impugning
Perfect	V-ing perfect
I could not have impugned you could not have impugned he could not have impugned we could not have impugned you could not have impugned they could not have impugned	I could not have been impugning you could not have been impugning he could not have been impugning we could not have been impugning you could not have been impugning they could not have been impugning

Interrogative form

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

Interro-negative form

Simple form	V-ing form
could I not impugn? could you not impugn? could he not impugn? could we not impugn? could you not impugn? could they not impugn?	could I not be impugning? could you not be impugning? could he not be impugning? could we not be impugning? could you not be impugning? could they not be impugning?
Perfect	V-ing perfect
could I not have impugned? could you not have impugned? could he not have impugned? could we not have impugned? could you not have impugned? could they not have impugned?	could I not have been impugning? could you not have been impugning? could he not have been impugning? could we not have been impugning? could you not have been impugning? could they not have been impugning?