Conjugación del verbo inglés
COULD SIGN

Verbo regular: sign - signed - signed

Afirmación

Forma simple	Forma con V-ing
I could sign you could sign she could sign we could sign you could sign they could sign	I could be signing you could be signing she could be signing we could be signing you could be signing they could be signing
Perfecto	Perfecto con V-ing
I could have signed you could have signed she could have signed we could have signed you could have signed they could have signed	I could have been signing you could have been signing she could have been signing we could have been signing you could have been signing they could have been signing

Negación

Forma simple	Forma con V-ing
I could not sign you could not sign she could not sign we could not sign you could not sign they could not sign	I could not be signing you could not be signing she could not be signing we could not be signing you could not be signing they could not be signing
Perfecto	Perfecto con V-ing
I could not have signed you could not have signed she could not have signed we could not have signed you could not have signed they could not have signed	I could not have been signing you could not have been signing she could not have been signing we could not have been signing you could not have been signing they could not have been signing

Forma interrogativa

Forma simple	Forma con V-ing
could I sign? could you sign? could she sign? could we sign? could you sign? could they sign?	could I be signing? could you be signing? could she be signing? could we be signing? could you be signing? could they be signing?
Perfecto	Perfecto con V-ing
could I have signed? could you have signed? could she have signed? could we have signed? could you have signed? could they have signed?	could I have been signing? could you have been signing? could she have been signing? could we have been signing? could you have been signing? could they have been signing?

Forma interro-negativa

Forma simple	Forma con V-ing
could I not sign? could you not sign? could she not sign? could we not sign? could you not sign? could they not sign?	could I not be signing? could you not be signing? could she not be signing? could we not be signing? could you not be signing? could they not be signing?
Perfecto	Perfecto con V-ing
could I not have signed? could you not have signed? could she not have signed? could we not have signed? could you not have signed? could they not have signed?	could I not have been signing? could you not have been signing? could she not have been signing? could we not have been signing? could you not have been signing? could they not have been signing?