English verb conjugation
COULD SAIL

Regular verb: sail - sailed - sailed

Affirmation

Simple form	V-ing form
I could sail you could sail she could sail we could sail you could sail they could sail	I could be sailing you could be sailing she could be sailing we could be sailing you could be sailing they could be sailing
Perfect	V-ing perfect
I could have sailed you could have sailed she could have sailed we could have sailed you could have sailed they could have sailed	I could have been sailing you could have been sailing she could have been sailing we could have been sailing you could have been sailing they could have been sailing

Negation

Simple form	V-ing form
I could not sail you could not sail she could not sail we could not sail you could not sail they could not sail	I could not be sailing you could not be sailing she could not be sailing we could not be sailing you could not be sailing they could not be sailing
Perfect	V-ing perfect
I could not have sailed you could not have sailed she could not have sailed we could not have sailed you could not have sailed they could not have sailed	I could not have been sailing you could not have been sailing she could not have been sailing we could not have been sailing you could not have been sailing they could not have been sailing

Interrogative form

Simple form	V-ing form
could I sail? could you sail? could she sail? could we sail? could you sail? could they sail?	could I be sailing? could you be sailing? could she be sailing? could we be sailing? could you be sailing? could they be sailing?
Perfect	V-ing perfect
could I have sailed? could you have sailed? could she have sailed? could we have sailed? could you have sailed? could they have sailed?	could I have been sailing? could you have been sailing? could she have been sailing? could we have been sailing? could you have been sailing? could they have been sailing?

Interro-negative form

Simple form	V-ing form
could I not sail? could you not sail? could she not sail? could we not sail? could you not sail? could they not sail?	could I not be sailing? could you not be sailing? could she not be sailing? could we not be sailing? could you not be sailing? could they not be sailing?
Perfect	V-ing perfect
could I not have sailed? could you not have sailed? could she not have sailed? could we not have sailed? could you not have sailed? could they not have sailed?	could I not have been sailing? could you not have been sailing? could she not have been sailing? could we not have been sailing? could you not have been sailing? could they not have been sailing?