English verb conjugation
COULD SING SING

Regular verb: sing sing - sing singed - sing singed

Warning, this verb may not exist. Conjugation is given as example.

Affirmation

Simple form	V-ing form
I could sing sing you could sing sing she could sing sing we could sing sing you could sing sing they could sing sing	I could be sing singing you could be sing singing she could be sing singing we could be sing singing you could be sing singing they could be sing singing
Perfect	V-ing perfect
I could have sing singed you could have sing singed she could have sing singed we could have sing singed you could have sing singed they could have sing singed	I could have been sing singing you could have been sing singing she could have been sing singing we could have been sing singing you could have been sing singing they could have been sing singing

Negation

Simple form	V-ing form
I could not sing sing you could not sing sing she could not sing sing we could not sing sing you could not sing sing they could not sing sing	I could not be sing singing you could not be sing singing she could not be sing singing we could not be sing singing you could not be sing singing they could not be sing singing
Perfect	V-ing perfect
I could not have sing singed you could not have sing singed she could not have sing singed we could not have sing singed you could not have sing singed they could not have sing singed	I could not have been sing singing you could not have been sing singing she could not have been sing singing we could not have been sing singing you could not have been sing singing they could not have been sing singing

Interrogative form

Simple form	V-ing form
could I sing sing? could you sing sing? could she sing sing? could we sing sing? could you sing sing? could they sing sing?	could I be sing singing? could you be sing singing? could she be sing singing? could we be sing singing? could you be sing singing? could they be sing singing?
Perfect	V-ing perfect
could I have sing singed? could you have sing singed? could she have sing singed? could we have sing singed? could you have sing singed? could they have sing singed?	could I have been sing singing? could you have been sing singing? could she have been sing singing? could we have been sing singing? could you have been sing singing? could they have been sing singing?

Interro-negative form

Simple form	V-ing form
could I not sing sing? could you not sing sing? could she not sing sing? could we not sing sing? could you not sing sing? could they not sing sing?	could I not be sing singing? could you not be sing singing? could she not be sing singing? could we not be sing singing? could you not be sing singing? could they not be sing singing?
Perfect	V-ing perfect
could I not have sing singed? could you not have sing singed? could she not have sing singed? could we not have sing singed? could you not have sing singed? could they not have sing singed?	could I not have been sing singing? could you not have been sing singing? could she not have been sing singing? could we not have been sing singing? could you not have been sing singing? could they not have been sing singing?