could excogitate
Regular verb: excogitate - excogitated- excogitated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could excogitate
you could excogitate
he could excogitate
we could excogitate
you could excogitate
they could excogitate 	I could be excogitating
you could be excogitating
he could be excogitating
we could be excogitating
you could be excogitating
they could be excogitating	I could have excogitated
you could have excogitated
he 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
he 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
he 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
he 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
he 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
he 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 he excogitate?
could we excogitate?
could you excogitate?
could they excogitate? 	could I be excogitating?
could you be excogitating?
could he be excogitating?
could we be excogitating?
could you be excogitating?
could they be excogitating? 	could I have excogitated?
could you have excogitated?
could he 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 he 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 he 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 he 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 he 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 he have been excogitating?
couldn't we have been excogitating?
couldn't you have been excogitating?
couldn't they have been excogitating?