I can sign you can sign he can sign we can sign you can sign they can sign
Forma com V-ing
I can be signing you can be signing he can be signing we can be signing you can be signing they can be signing
Perfeito
I can have signed you can have signed he can have signed we can have signed you can have signed they can have signed
Perfeito com V-ing
I can have been signing you can have been signing he can have been signing we can have been signing you can have been signing they can have been signing
Negação
Forma simple
I cannot sign you cannot sign he cannot sign we cannot sign you cannot sign they cannot sign
Forma com V-ing
I cannot be signing you cannot be signing he cannot be signing we cannot be signing you cannot be signing they cannot be signing
Perfeito
I cannot have signed you cannot have signed he cannot have signed we cannot have signed you cannot have signed they cannot have signed
Perfeito com V-ing
I cannot have been signing you cannot have been signing he cannot have been signing we cannot have been signing you cannot have been signing they cannot have been signing
Forma interrogativa
Forma simple
can I sign? can you sign? can he sign? can we sign? can you sign? can they sign?
Forma com V-ing
can I be signing? can you be signing? can he be signing? can we be signing? can you be signing? can they be signing?
Perfeito
can I have signed? can you have signed? can he have signed? can we have signed? can you have signed? can they have signed?
Perfeito com V-ing
can I have been signing? can you have been signing? can he have been signing? can we have been signing? can you have been signing? can they have been signing?
Forma interro-Negação
Forma simple
can I not sign? can you not sign? can he not sign? can we not sign? can you not sign? can they not sign?
Forma com V-ing
can I not be signing? can you not be signing? can he not be signing? can we not be signing? can you not be signing? can they not be signing?
Perfeito
can I not have signed? can you not have signed? can he not have signed? can we not have signed? can you not have signed? can they not have signed?
Perfeito com V-ing
can I not have been signing? can you not have been signing? can he not have been signing? can we not have been signing? can you not have been signing? can they not have been signing?