I can refer you can refer she can refer we can refer you can refer they can refer
Forma con V-ing
I can be referring you can be referring she can be referring we can be referring you can be referring they can be referring
Perfecto
I can have referred you can have referred she can have referred we can have referred you can have referred they can have referred
Perfecto con V-ing
I can have been referring you can have been referring she can have been referring we can have been referring you can have been referring they can have been referring
Negación
Forma simple
I cannot refer you cannot refer she cannot refer we cannot refer you cannot refer they cannot refer
Forma con V-ing
I cannot be referring you cannot be referring she cannot be referring we cannot be referring you cannot be referring they cannot be referring
Perfecto
I cannot have referred you cannot have referred she cannot have referred we cannot have referred you cannot have referred they cannot have referred
Perfecto con V-ing
I cannot have been referring you cannot have been referring she cannot have been referring we cannot have been referring you cannot have been referring they cannot have been referring
Forma interrogativa
Forma simple
can I refer? can you refer? can she refer? can we refer? can you refer? can they refer?
Forma con V-ing
can I be referring? can you be referring? can she be referring? can we be referring? can you be referring? can they be referring?
Perfecto
can I have referred? can you have referred? can she have referred? can we have referred? can you have referred? can they have referred?
Perfecto con V-ing
can I have been referring? can you have been referring? can she have been referring? can we have been referring? can you have been referring? can they have been referring?
Forma interro-negativa
Forma simple
can I not refer? can you not refer? can she not refer? can we not refer? can you not refer? can they not refer?
Forma con V-ing
can I not be referring? can you not be referring? can she not be referring? can we not be referring? can you not be referring? can they not be referring?
Perfecto
can I not have referred? can you not have referred? can she not have referred? can we not have referred? can you not have referred? can they not have referred?
Perfecto con V-ing
can I not have been referring? can you not have been referring? can she not have been referring? can we not have been referring? can you not have been referring? can they not have been referring?