English verb conjugation
COULD EXCEL

Regular verb: excel - excelled - excelled

Affirmation

Simple form	V-ing form
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
Perfect	V-ing perfect
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
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
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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
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?
Perfect	V-ing perfect
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?