English verb conjugation
COULD TACK

Regular verb: tack - tacked - tacked

Affirmation

Simple form	V-ing form
I could tack you could tack he could tack we could tack you could tack they could tack	I could be tacking you could be tacking he could be tacking we could be tacking you could be tacking they could be tacking
Perfect	V-ing perfect
I could have tacked you could have tacked he could have tacked we could have tacked you could have tacked they could have tacked	I could have been tacking you could have been tacking he could have been tacking we could have been tacking you could have been tacking they could have been tacking

Negation

Simple form	V-ing form
I couldn't tack you couldn't tack he couldn't tack we couldn't tack you couldn't tack they couldn't tack	I couldn't be tacking you couldn't be tacking he couldn't be tacking we couldn't be tacking you couldn't be tacking they couldn't be tacking
Perfect	V-ing perfect
I couldn't have tacked you couldn't have tacked he couldn't have tacked we couldn't have tacked you couldn't have tacked they couldn't have tacked	I couldn't have been tacking you couldn't have been tacking he couldn't have been tacking we couldn't have been tacking you couldn't have been tacking they couldn't have been tacking

Interrogative form

Simple form	V-ing form
could I tack? could you tack? could he tack? could we tack? could you tack? could they tack?	could I be tacking? could you be tacking? could he be tacking? could we be tacking? could you be tacking? could they be tacking?
Perfect	V-ing perfect
could I have tacked? could you have tacked? could he have tacked? could we have tacked? could you have tacked? could they have tacked?	could I have been tacking? could you have been tacking? could he have been tacking? could we have been tacking? could you have been tacking? could they have been tacking?

Interro-negative form

Simple form	V-ing form
couldn't I tack? couldn't you tack? couldn't he tack? couldn't we tack? couldn't you tack? couldn't they tack?	couldn't I be tacking? couldn't you be tacking? couldn't he be tacking? couldn't we be tacking? couldn't you be tacking? couldn't they be tacking?
Perfect	V-ing perfect
couldn't I have tacked? couldn't you have tacked? couldn't he have tacked? couldn't we have tacked? couldn't you have tacked? couldn't they have tacked?	couldn't I have been tacking? couldn't you have been tacking? couldn't he have been tacking? couldn't we have been tacking? couldn't you have been tacking? couldn't they have been tacking?