can impugn
Regular verb: impugn - impugned- impugned

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