English verb conjugation
COULD STAIN

Regular verb: stain - stained - stained

Affirmation

Simple form	V-ing form
I could stain you could stain he could stain we could stain you could stain they could stain	I could be staining you could be staining he could be staining we could be staining you could be staining they could be staining
Perfect	V-ing perfect
I could have stained you could have stained he could have stained we could have stained you could have stained they could have stained	I could have been staining you could have been staining he could have been staining we could have been staining you could have been staining they could have been staining

Negation

Simple form	V-ing form
I couldn't stain you couldn't stain he couldn't stain we couldn't stain you couldn't stain they couldn't stain	I couldn't be staining you couldn't be staining he couldn't be staining we couldn't be staining you couldn't be staining they couldn't be staining
Perfect	V-ing perfect
I couldn't have stained you couldn't have stained he couldn't have stained we couldn't have stained you couldn't have stained they couldn't have stained	I couldn't have been staining you couldn't have been staining he couldn't have been staining we couldn't have been staining you couldn't have been staining they couldn't have been staining

Interrogative form

Simple form	V-ing form
could I stain? could you stain? could he stain? could we stain? could you stain? could they stain?	could I be staining? could you be staining? could he be staining? could we be staining? could you be staining? could they be staining?
Perfect	V-ing perfect
could I have stained? could you have stained? could he have stained? could we have stained? could you have stained? could they have stained?	could I have been staining? could you have been staining? could he have been staining? could we have been staining? could you have been staining? could they have been staining?

Interro-negative form

Simple form	V-ing form
couldn't I stain? couldn't you stain? couldn't he stain? couldn't we stain? couldn't you stain? couldn't they stain?	couldn't I be staining? couldn't you be staining? couldn't he be staining? couldn't we be staining? couldn't you be staining? couldn't they be staining?
Perfect	V-ing perfect
couldn't I have stained? couldn't you have stained? couldn't he have stained? couldn't we have stained? couldn't you have stained? couldn't they have stained?	couldn't I have been staining? couldn't you have been staining? couldn't he have been staining? couldn't we have been staining? couldn't you have been staining? couldn't they have been staining?