can invalidate
Regular verb: invalidate - invalidated- invalidated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can invalidate
you can invalidate
she can invalidate
we can invalidate
you can invalidate
they can invalidate 	I can be invalidating
you can be invalidating
she can be invalidating
we can be invalidating
you can be invalidating
they can be invalidating	I can have invalidated
you can have invalidated
she can have invalidated
we can have invalidated
you can have invalidated
they can have invalidated	I can have been invalidating
you can have been invalidating
she can have been invalidating
we can have been invalidating
you can have been invalidating
they can have been invalidating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot invalidate
you cannot invalidate
she cannot invalidate
we cannot invalidate
you cannot invalidate
they cannot invalidate 	I cannot be invalidating
you cannot be invalidating
she cannot be invalidating
we cannot be invalidating
you cannot be invalidating
they cannot be invalidating	I cannot have invalidated
you cannot have invalidated
she cannot have invalidated
we cannot have invalidated
you cannot have invalidated
they cannot have invalidated	I cannot have been invalidating
you cannot have been invalidating
she cannot have been invalidating
we cannot have been invalidating
you cannot have been invalidating
they cannot have been invalidating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I invalidate?
can you invalidate?
can she invalidate?
can we invalidate?
can you invalidate?
can they invalidate? 	can I be invalidating?
can you be invalidating?
can she be invalidating?
can we be invalidating?
can you be invalidating?
can they be invalidating? 	can I have invalidated?
can you have invalidated?
can she have invalidated?
can we have invalidated?
can you have invalidated?
can they have invalidated? 	can I have been invalidating?
can you have been invalidating?
can she have been invalidating?
can we have been invalidating?
can you have been invalidating?
can they have been invalidating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not invalidate?
can you not invalidate?
can she not invalidate?
can we not invalidate?
can you not invalidate?
can they not invalidate? 	can I not be invalidating?
can you not be invalidating?
can she not be invalidating?
can we not be invalidating?
can you not be invalidating?
can they not be invalidating? 	can I not have invalidated?
can you not have invalidated?
can she not have invalidated?
can we not have invalidated?
can you not have invalidated?
can they not have invalidated? 	can I not have been invalidating?
can you not have been invalidating?
can she not have been invalidating?
can we not have been invalidating?
can you not have been invalidating?
can they not have been invalidating?