I can sire you can sire she can sire we can sire you can sire they can sire
V-ing form
I can be siring you can be siring she can be siring we can be siring you can be siring they can be siring
Perfect
I can have sired you can have sired she can have sired we can have sired you can have sired they can have sired
V-ing perfect
I can have been siring you can have been siring she can have been siring we can have been siring you can have been siring they can have been siring
Negation
Simple form
I cannot sire you cannot sire she cannot sire we cannot sire you cannot sire they cannot sire
V-ing form
I cannot be siring you cannot be siring she cannot be siring we cannot be siring you cannot be siring they cannot be siring
Perfect
I cannot have sired you cannot have sired she cannot have sired we cannot have sired you cannot have sired they cannot have sired
V-ing perfect
I cannot have been siring you cannot have been siring she cannot have been siring we cannot have been siring you cannot have been siring they cannot have been siring
Interrogative form
Simple form
can I sire? can you sire? can she sire? can we sire? can you sire? can they sire?
V-ing form
can I be siring? can you be siring? can she be siring? can we be siring? can you be siring? can they be siring?
Perfect
can I have sired? can you have sired? can she have sired? can we have sired? can you have sired? can they have sired?
V-ing perfect
can I have been siring? can you have been siring? can she have been siring? can we have been siring? can you have been siring? can they have been siring?
Interro-negative form
Simple form
can I not sire? can you not sire? can she not sire? can we not sire? can you not sire? can they not sire?
V-ing form
can I not be siring? can you not be siring? can she not be siring? can we not be siring? can you not be siring? can they not be siring?
Perfect
can I not have sired? can you not have sired? can she not have sired? can we not have sired? can you not have sired? can they not have sired?
V-ing perfect
can I not have been siring? can you not have been siring? can she not have been siring? can we not have been siring? can you not have been siring? can they not have been siring?