English verb conjugation
COULD SUE

Regular verb: sue - sued - sued

Affirmation

Simple form	V-ing form
I could sue you could sue he could sue we could sue you could sue they could sue	I could be suing you could be suing he could be suing we could be suing you could be suing they could be suing
Perfect	V-ing perfect
I could have sued you could have sued he could have sued we could have sued you could have sued they could have sued	I could have been suing you could have been suing he could have been suing we could have been suing you could have been suing they could have been suing

Negation

Simple form	V-ing form
I couldn't sue you couldn't sue he couldn't sue we couldn't sue you couldn't sue they couldn't sue	I couldn't be suing you couldn't be suing he couldn't be suing we couldn't be suing you couldn't be suing they couldn't be suing
Perfect	V-ing perfect
I couldn't have sued you couldn't have sued he couldn't have sued we couldn't have sued you couldn't have sued they couldn't have sued	I couldn't have been suing you couldn't have been suing he couldn't have been suing we couldn't have been suing you couldn't have been suing they couldn't have been suing

Interrogative form

Simple form	V-ing form
could I sue? could you sue? could he sue? could we sue? could you sue? could they sue?	could I be suing? could you be suing? could he be suing? could we be suing? could you be suing? could they be suing?
Perfect	V-ing perfect
could I have sued? could you have sued? could he have sued? could we have sued? could you have sued? could they have sued?	could I have been suing? could you have been suing? could he have been suing? could we have been suing? could you have been suing? could they have been suing?

Interro-negative form

Simple form	V-ing form
couldn't I sue? couldn't you sue? couldn't he sue? couldn't we sue? couldn't you sue? couldn't they sue?	couldn't I be suing? couldn't you be suing? couldn't he be suing? couldn't we be suing? couldn't you be suing? couldn't they be suing?
Perfect	V-ing perfect
couldn't I have sued? couldn't you have sued? couldn't he have sued? couldn't we have sued? couldn't you have sued? couldn't they have sued?	couldn't I have been suing? couldn't you have been suing? couldn't he have been suing? couldn't we have been suing? couldn't you have been suing? couldn't they have been suing?