English verb conjugation
COULD LACK

Regular verb: lack - lacked - lacked

Affirmation

Simple form	V-ing form
I could lack you could lack he could lack we could lack you could lack they could lack	I could be lacking you could be lacking he could be lacking we could be lacking you could be lacking they could be lacking
Perfect	V-ing perfect
I could have lacked you could have lacked he could have lacked we could have lacked you could have lacked they could have lacked	I could have been lacking you could have been lacking he could have been lacking we could have been lacking you could have been lacking they could have been lacking

Negation

Simple form	V-ing form
I couldn't lack you couldn't lack he couldn't lack we couldn't lack you couldn't lack they couldn't lack	I couldn't be lacking you couldn't be lacking he couldn't be lacking we couldn't be lacking you couldn't be lacking they couldn't be lacking
Perfect	V-ing perfect
I couldn't have lacked you couldn't have lacked he couldn't have lacked we couldn't have lacked you couldn't have lacked they couldn't have lacked	I couldn't have been lacking you couldn't have been lacking he couldn't have been lacking we couldn't have been lacking you couldn't have been lacking they couldn't have been lacking

Interrogative form

Simple form	V-ing form
could I lack? could you lack? could he lack? could we lack? could you lack? could they lack?	could I be lacking? could you be lacking? could he be lacking? could we be lacking? could you be lacking? could they be lacking?
Perfect	V-ing perfect
could I have lacked? could you have lacked? could he have lacked? could we have lacked? could you have lacked? could they have lacked?	could I have been lacking? could you have been lacking? could he have been lacking? could we have been lacking? could you have been lacking? could they have been lacking?

Interro-negative form

Simple form	V-ing form
couldn't I lack? couldn't you lack? couldn't he lack? couldn't we lack? couldn't you lack? couldn't they lack?	couldn't I be lacking? couldn't you be lacking? couldn't he be lacking? couldn't we be lacking? couldn't you be lacking? couldn't they be lacking?
Perfect	V-ing perfect
couldn't I have lacked? couldn't you have lacked? couldn't he have lacked? couldn't we have lacked? couldn't you have lacked? couldn't they have lacked?	couldn't I have been lacking? couldn't you have been lacking? couldn't he have been lacking? couldn't we have been lacking? couldn't you have been lacking? couldn't they have been lacking?