I could modify you could modify she could modify we could modify you could modify they could modify
Forma con V-ing
I could be modifying you could be modifying she could be modifying we could be modifying you could be modifying they could be modifying
Perfecto
I could have modified you could have modified she could have modified we could have modified you could have modified they could have modified
Perfecto con V-ing
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
Negación
Forma simple
I couldn't modify you couldn't modify she couldn't modify we couldn't modify you couldn't modify they couldn't modify
Forma con V-ing
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
Perfecto
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
Perfecto con V-ing
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
Forma interrogativa
Forma simple
could I modify? could you modify? could she modify? could we modify? could you modify? could they modify?
Forma con V-ing
could I be modifying? could you be modifying? could she be modifying? could we be modifying? could you be modifying? could they be modifying?
Perfecto
could I have modified? could you have modified? could she have modified? could we have modified? could you have modified? could they have modified?
Perfecto con V-ing
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?
Forma interro-negativa
Forma simple
couldn't I modify? couldn't you modify? couldn't she modify? couldn't we modify? couldn't you modify? couldn't they modify?
Forma con V-ing
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?
Perfecto
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?
Perfecto con V-ing
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?