could excogitate
Regular verb: excogitate - excogitated- excogitated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could excogitate
you could excogitate
she could excogitate
we could excogitate
you could excogitate
they could excogitate 	I could be excogitating
you could be excogitating
she could be excogitating
we could be excogitating
you could be excogitating
they could be excogitating	I could have excogitated
you could have excogitated
she could have excogitated
we could have excogitated
you could have excogitated
they could have excogitated	I could have been excogitating
you could have been excogitating
she could have been excogitating
we could have been excogitating
you could have been excogitating
they could have been excogitating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't excogitate
you couldn't excogitate
she couldn't excogitate
we couldn't excogitate
you couldn't excogitate
they couldn't excogitate 	I couldn't be excogitating
you couldn't be excogitating
she couldn't be excogitating
we couldn't be excogitating
you couldn't be excogitating
they couldn't be excogitating	I couldn't have excogitated
you couldn't have excogitated
she couldn't have excogitated
we couldn't have excogitated
you couldn't have excogitated
they couldn't have excogitated	I couldn't have been excogitating
you couldn't have been excogitating
she couldn't have been excogitating
we couldn't have been excogitating
you couldn't have been excogitating
they couldn't have been excogitating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I excogitate?
could you excogitate?
could she excogitate?
could we excogitate?
could you excogitate?
could they excogitate? 	could I be excogitating?
could you be excogitating?
could she be excogitating?
could we be excogitating?
could you be excogitating?
could they be excogitating? 	could I have excogitated?
could you have excogitated?
could she have excogitated?
could we have excogitated?
could you have excogitated?
could they have excogitated? 	could I have been excogitating?
could you have been excogitating?
could she have been excogitating?
could we have been excogitating?
could you have been excogitating?
could they have been excogitating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I excogitate?
couldn't you excogitate?
couldn't she excogitate?
couldn't we excogitate?
couldn't you excogitate?
couldn't they excogitate? 	couldn't I be excogitating?
couldn't you be excogitating?
couldn't she be excogitating?
couldn't we be excogitating?
couldn't you be excogitating?
couldn't they be excogitating? 	couldn't I have excogitated?
couldn't you have excogitated?
couldn't she have excogitated?
couldn't we have excogitated?
couldn't you have excogitated?
couldn't they have excogitated? 	couldn't I have been excogitating?
couldn't you have been excogitating?
couldn't she have been excogitating?
couldn't we have been excogitating?
couldn't you have been excogitating?
couldn't they have been excogitating?