English verb conjugation
COULD CONCERN

Regular verb: concern - concerned - concerned

Affirmation

Simple form	V-ing form
I could concern you could concern she could concern we could concern you could concern they could concern	I could be concerning you could be concerning she could be concerning we could be concerning you could be concerning they could be concerning
Perfect	V-ing perfect
I could have concerned you could have concerned she could have concerned we could have concerned you could have concerned they could have concerned	I could have been concerning you could have been concerning she could have been concerning we could have been concerning you could have been concerning they could have been concerning

Negation

Simple form	V-ing form
I couldn't concern you couldn't concern she couldn't concern we couldn't concern you couldn't concern they couldn't concern	I couldn't be concerning you couldn't be concerning she couldn't be concerning we couldn't be concerning you couldn't be concerning they couldn't be concerning
Perfect	V-ing perfect
I couldn't have concerned you couldn't have concerned she couldn't have concerned we couldn't have concerned you couldn't have concerned they couldn't have concerned	I couldn't have been concerning you couldn't have been concerning she couldn't have been concerning we couldn't have been concerning you couldn't have been concerning they couldn't have been concerning

Interrogative form

Simple form	V-ing form
could I concern? could you concern? could she concern? could we concern? could you concern? could they concern?	could I be concerning? could you be concerning? could she be concerning? could we be concerning? could you be concerning? could they be concerning?
Perfect	V-ing perfect
could I have concerned? could you have concerned? could she have concerned? could we have concerned? could you have concerned? could they have concerned?	could I have been concerning? could you have been concerning? could she have been concerning? could we have been concerning? could you have been concerning? could they have been concerning?

Interro-negative form

Simple form	V-ing form
couldn't I concern? couldn't you concern? couldn't she concern? couldn't we concern? couldn't you concern? couldn't they concern?	couldn't I be concerning? couldn't you be concerning? couldn't she be concerning? couldn't we be concerning? couldn't you be concerning? couldn't they be concerning?
Perfect	V-ing perfect
couldn't I have concerned? couldn't you have concerned? couldn't she have concerned? couldn't we have concerned? couldn't you have concerned? couldn't they have concerned?	couldn't I have been concerning? couldn't you have been concerning? couldn't she have been concerning? couldn't we have been concerning? couldn't you have been concerning? couldn't they have been concerning?