could invoke
Regular verb: invoke - invoked- invoked

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could invoke
you could invoke
she could invoke
we could invoke
you could invoke
they could invoke 	I could be invoking
you could be invoking
she could be invoking
we could be invoking
you could be invoking
they could be invoking	I could have invoked
you could have invoked
she could have invoked
we could have invoked
you could have invoked
they could have invoked	I could have been invoking
you could have been invoking
she could have been invoking
we could have been invoking
you could have been invoking
they could have been invoking	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't invoke
you couldn't invoke
she couldn't invoke
we couldn't invoke
you couldn't invoke
they couldn't invoke 	I couldn't be invoking
you couldn't be invoking
she couldn't be invoking
we couldn't be invoking
you couldn't be invoking
they couldn't be invoking	I couldn't have invoked
you couldn't have invoked
she couldn't have invoked
we couldn't have invoked
you couldn't have invoked
they couldn't have invoked	I couldn't have been invoking
you couldn't have been invoking
she couldn't have been invoking
we couldn't have been invoking
you couldn't have been invoking
they couldn't have been invoking	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I invoke?
could you invoke?
could she invoke?
could we invoke?
could you invoke?
could they invoke? 	could I be invoking?
could you be invoking?
could she be invoking?
could we be invoking?
could you be invoking?
could they be invoking? 	could I have invoked?
could you have invoked?
could she have invoked?
could we have invoked?
could you have invoked?
could they have invoked? 	could I have been invoking?
could you have been invoking?
could she have been invoking?
could we have been invoking?
could you have been invoking?
could they have been invoking? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I invoke?
couldn't you invoke?
couldn't she invoke?
couldn't we invoke?
couldn't you invoke?
couldn't they invoke? 	couldn't I be invoking?
couldn't you be invoking?
couldn't she be invoking?
couldn't we be invoking?
couldn't you be invoking?
couldn't they be invoking? 	couldn't I have invoked?
couldn't you have invoked?
couldn't she have invoked?
couldn't we have invoked?
couldn't you have invoked?
couldn't they have invoked? 	couldn't I have been invoking?
couldn't you have been invoking?
couldn't she have been invoking?
couldn't we have been invoking?
couldn't you have been invoking?
couldn't they have been invoking?