English verb conjugation
COULD MODIFY

Regular verb: modify - modified - modified

Affirmation

Simple form	V-ing form
I could modify you could modify she could modify we could modify you could modify they could modify	I could be modifying you could be modifying she could be modifying we could be modifying you could be modifying they could be modifying
Perfect	V-ing perfect
I could have modified you could have modified she could have modified we could have modified you could have modified they could have modified	I could have been modifying you could have been modifying she could have been modifying we could have been modifying you could have been modifying they could have been modifying

Negation

Simple form	V-ing form
I couldn't modify you couldn't modify she couldn't modify we couldn't modify you couldn't modify they couldn't modify	I couldn't be modifying you couldn't be modifying she couldn't be modifying we couldn't be modifying you couldn't be modifying they couldn't be modifying
Perfect	V-ing perfect
I couldn't have modified you couldn't have modified she couldn't have modified we couldn't have modified you couldn't have modified they couldn't have modified	I couldn't have been modifying you couldn't have been modifying she couldn't have been modifying we couldn't have been modifying you couldn't have been modifying they couldn't have been modifying

Interrogative form

Simple form	V-ing form
could I modify? could you modify? could she modify? could we modify? could you modify? could they modify?	could I be modifying? could you be modifying? could she be modifying? could we be modifying? could you be modifying? could they be modifying?
Perfect	V-ing perfect
could I have modified? could you have modified? could she have modified? could we have modified? could you have modified? could they have modified?	could I have been modifying? could you have been modifying? could she have been modifying? could we have been modifying? could you have been modifying? could they have been modifying?

Interro-negative form

Simple form	V-ing form
couldn't I modify? couldn't you modify? couldn't she modify? couldn't we modify? couldn't you modify? couldn't they modify?	couldn't I be modifying? couldn't you be modifying? couldn't she be modifying? couldn't we be modifying? couldn't you be modifying? couldn't they be modifying?
Perfect	V-ing perfect
couldn't I have modified? couldn't you have modified? couldn't she have modified? couldn't we have modified? couldn't you have modified? couldn't they have modified?	couldn't I have been modifying? couldn't you have been modifying? couldn't she have been modifying? couldn't we have been modifying? couldn't you have been modifying? couldn't they have been modifying?