can invalid
Regular verb: invalid - invalided- invalided

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I can invalid
you can invalid
she can invalid
we can invalid
you can invalid
they can invalid 	I can be invaliding
you can be invaliding
she can be invaliding
we can be invaliding
you can be invaliding
they can be invaliding	I can have invalided
you can have invalided
she can have invalided
we can have invalided
you can have invalided
they can have invalided	I can have been invaliding
you can have been invaliding
she can have been invaliding
we can have been invaliding
you can have been invaliding
they can have been invaliding	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I cannot invalid
you cannot invalid
she cannot invalid
we cannot invalid
you cannot invalid
they cannot invalid 	I cannot be invaliding
you cannot be invaliding
she cannot be invaliding
we cannot be invaliding
you cannot be invaliding
they cannot be invaliding	I cannot have invalided
you cannot have invalided
she cannot have invalided
we cannot have invalided
you cannot have invalided
they cannot have invalided	I cannot have been invaliding
you cannot have been invaliding
she cannot have been invaliding
we cannot have been invaliding
you cannot have been invaliding
they cannot have been invaliding	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I invalid?
can you invalid?
can she invalid?
can we invalid?
can you invalid?
can they invalid? 	can I be invaliding?
can you be invaliding?
can she be invaliding?
can we be invaliding?
can you be invaliding?
can they be invaliding? 	can I have invalided?
can you have invalided?
can she have invalided?
can we have invalided?
can you have invalided?
can they have invalided? 	can I have been invaliding?
can you have been invaliding?
can she have been invaliding?
can we have been invaliding?
can you have been invaliding?
can they have been invaliding? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
can I not invalid?
can you not invalid?
can she not invalid?
can we not invalid?
can you not invalid?
can they not invalid? 	can I not be invaliding?
can you not be invaliding?
can she not be invaliding?
can we not be invaliding?
can you not be invaliding?
can they not be invaliding? 	can I not have invalided?
can you not have invalided?
can she not have invalided?
can we not have invalided?
can you not have invalided?
can they not have invalided? 	can I not have been invaliding?
can you not have been invaliding?
can she not have been invaliding?
can we not have been invaliding?
can you not have been invaliding?
can they not have been invaliding?