English verb conjugation
COULD UNZIP

Regular verb: unzip - unziped - unziped

Affirmation

Simple form	V-ing form
I could unzip you could unzip he could unzip we could unzip you could unzip they could unzip	I could be unziping you could be unziping he could be unziping we could be unziping you could be unziping they could be unziping
Perfect	V-ing perfect
I could have unziped you could have unziped he could have unziped we could have unziped you could have unziped they could have unziped	I could have been unziping you could have been unziping he could have been unziping we could have been unziping you could have been unziping they could have been unziping

Negation

Simple form	V-ing form
I couldn't unzip you couldn't unzip he couldn't unzip we couldn't unzip you couldn't unzip they couldn't unzip	I couldn't be unziping you couldn't be unziping he couldn't be unziping we couldn't be unziping you couldn't be unziping they couldn't be unziping
Perfect	V-ing perfect
I couldn't have unziped you couldn't have unziped he couldn't have unziped we couldn't have unziped you couldn't have unziped they couldn't have unziped	I couldn't have been unziping you couldn't have been unziping he couldn't have been unziping we couldn't have been unziping you couldn't have been unziping they couldn't have been unziping

Interrogative form

Simple form	V-ing form
could I unzip? could you unzip? could he unzip? could we unzip? could you unzip? could they unzip?	could I be unziping? could you be unziping? could he be unziping? could we be unziping? could you be unziping? could they be unziping?
Perfect	V-ing perfect
could I have unziped? could you have unziped? could he have unziped? could we have unziped? could you have unziped? could they have unziped?	could I have been unziping? could you have been unziping? could he have been unziping? could we have been unziping? could you have been unziping? could they have been unziping?

Interro-negative form

Simple form	V-ing form
couldn't I unzip? couldn't you unzip? couldn't he unzip? couldn't we unzip? couldn't you unzip? couldn't they unzip?	couldn't I be unziping? couldn't you be unziping? couldn't he be unziping? couldn't we be unziping? couldn't you be unziping? couldn't they be unziping?
Perfect	V-ing perfect
couldn't I have unziped? couldn't you have unziped? couldn't he have unziped? couldn't we have unziped? couldn't you have unziped? couldn't they have unziped?	couldn't I have been unziping? couldn't you have been unziping? couldn't he have been unziping? couldn't we have been unziping? couldn't you have been unziping? couldn't they have been unziping?