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 couldn't zip you couldn't zip he couldn't zip we couldn't zip you couldn't zip they couldn't zip	I couldn't be zipping you couldn't be zipping he couldn't be zipping we couldn't be zipping you couldn't be zipping they couldn't be zipping
Perfect	V-ing perfect
I couldn't have zipped you couldn't have zipped he couldn't have zipped we couldn't have zipped you couldn't have zipped they couldn't have zipped	I couldn't have been zipping you couldn't have been zipping he couldn't have been zipping we couldn't have been zipping you couldn't have been zipping they couldn't 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
couldn't I zip? couldn't you zip? couldn't he zip? couldn't we zip? couldn't you zip? couldn't they zip?	couldn't I be zipping? couldn't you be zipping? couldn't he be zipping? couldn't we be zipping? couldn't you be zipping? couldn't they be zipping?
Perfect	V-ing perfect
couldn't I have zipped? couldn't you have zipped? couldn't he have zipped? couldn't we have zipped? couldn't you have zipped? couldn't they have zipped?	couldn't I have been zipping? couldn't you have been zipping? couldn't he have been zipping? couldn't we have been zipping? couldn't you have been zipping? couldn't they have been zipping?