English verb conjugation
COULD ZIP

Regular verb: zip - zipped - zipped

Affirmation

Simple form	V-ing form
I could zip you could zip he could zip we could zip you could zip they could zip	I could be zipping you could be zipping he could be zipping we could be zipping you could be zipping they could be zipping
Perfect	V-ing perfect
I could have zipped you could have zipped he could have zipped we could have zipped you could have zipped they could have zipped	I could have been zipping you could have been zipping he could have been zipping we could have been zipping you could have been zipping they could have been zipping

Negation

Simple form	V-ing form
I could not zip you could not zip he could not zip we could not zip you could not zip they could not zip	I could not be zipping you could not be zipping he could not be zipping we could not be zipping you could not be zipping they could not be zipping
Perfect	V-ing perfect
I could not have zipped you could not have zipped he could not have zipped we could not have zipped you could not have zipped they could not have zipped	I could not have been zipping you could not have been zipping he could not have been zipping we could not have been zipping you could not have been zipping they could not have been zipping

Interrogative form

Simple form	V-ing form
could I zip? could you zip? could he zip? could we zip? could you zip? could they zip?	could I be zipping? could you be zipping? could he be zipping? could we be zipping? could you be zipping? could they be zipping?
Perfect	V-ing perfect
could I have zipped? could you have zipped? could he have zipped? could we have zipped? could you have zipped? could they have zipped?	could I have been zipping? could you have been zipping? could he have been zipping? could we have been zipping? could you have been zipping? could they have been zipping?

Interro-negative form

Simple form	V-ing form
could I not zip? could you not zip? could he not zip? could we not zip? could you not zip? could they not zip?	could I not be zipping? could you not be zipping? could he not be zipping? could we not be zipping? could you not be zipping? could they not be zipping?
Perfect	V-ing perfect
could I not have zipped? could you not have zipped? could he not have zipped? could we not have zipped? could you not have zipped? could they not have zipped?	could I not have been zipping? could you not have been zipping? could he not have been zipping? could we not have been zipping? could you not have been zipping? could they not have been zipping?