English verb conjugation
CAN LACK

Regular verb: lack - lacked - lacked

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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