could excel
Regular verb: excel - excelled- excelled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I could excel
you could excel
she could excel
we could excel
you could excel
they could excel 	I could be excelling
you could be excelling
she could be excelling
we could be excelling
you could be excelling
they could be excelling	I could have excelled
you could have excelled
she could have excelled
we could have excelled
you could have excelled
they could have excelled	I could have been excelling
you could have been excelling
she could have been excelling
we could have been excelling
you could have been excelling
they could have been excelling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I couldn't excel
you couldn't excel
she couldn't excel
we couldn't excel
you couldn't excel
they couldn't excel 	I couldn't be excelling
you couldn't be excelling
she couldn't be excelling
we couldn't be excelling
you couldn't be excelling
they couldn't be excelling	I couldn't have excelled
you couldn't have excelled
she couldn't have excelled
we couldn't have excelled
you couldn't have excelled
they couldn't have excelled	I couldn't have been excelling
you couldn't have been excelling
she couldn't have been excelling
we couldn't have been excelling
you couldn't have been excelling
they couldn't have been excelling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
could I excel?
could you excel?
could she excel?
could we excel?
could you excel?
could they excel? 	could I be excelling?
could you be excelling?
could she be excelling?
could we be excelling?
could you be excelling?
could they be excelling? 	could I have excelled?
could you have excelled?
could she have excelled?
could we have excelled?
could you have excelled?
could they have excelled? 	could I have been excelling?
could you have been excelling?
could she have been excelling?
could we have been excelling?
could you have been excelling?
could they have been excelling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
couldn't I excel?
couldn't you excel?
couldn't she excel?
couldn't we excel?
couldn't you excel?
couldn't they excel? 	couldn't I be excelling?
couldn't you be excelling?
couldn't she be excelling?
couldn't we be excelling?
couldn't you be excelling?
couldn't they be excelling? 	couldn't I have excelled?
couldn't you have excelled?
couldn't she have excelled?
couldn't we have excelled?
couldn't you have excelled?
couldn't they have excelled? 	couldn't I have been excelling?
couldn't you have been excelling?
couldn't she have been excelling?
couldn't we have been excelling?
couldn't you have been excelling?
couldn't they have been excelling?