I could excise you could excise he could excise we could excise you could excise they could excise
V-ing form
I could be excising you could be excising he could be excising we could be excising you could be excising they could be excising
Perfect
I could have excised you could have excised he could have excised we could have excised you could have excised they could have excised
V-ing perfect
I could have been excising you could have been excising he could have been excising we could have been excising you could have been excising they could have been excising
Negation
Simple form
I could not excise you could not excise he could not excise we could not excise you could not excise they could not excise
V-ing form
I could not be excising you could not be excising he could not be excising we could not be excising you could not be excising they could not be excising
Perfect
I could not have excised you could not have excised he could not have excised we could not have excised you could not have excised they could not have excised
V-ing perfect
I could not have been excising you could not have been excising he could not have been excising we could not have been excising you could not have been excising they could not have been excising
Interrogative form
Simple form
could I excise? could you excise? could he excise? could we excise? could you excise? could they excise?
V-ing form
could I be excising? could you be excising? could he be excising? could we be excising? could you be excising? could they be excising?
Perfect
could I have excised? could you have excised? could he have excised? could we have excised? could you have excised? could they have excised?
V-ing perfect
could I have been excising? could you have been excising? could he have been excising? could we have been excising? could you have been excising? could they have been excising?
Interro-negative form
Simple form
could I not excise? could you not excise? could he not excise? could we not excise? could you not excise? could they not excise?
V-ing form
could I not be excising? could you not be excising? could he not be excising? could we not be excising? could you not be excising? could they not be excising?
Perfect
could I not have excised? could you not have excised? could he not have excised? could we not have excised? could you not have excised? could they not have excised?
V-ing perfect
could I not have been excising? could you not have been excising? could he not have been excising? could we not have been excising? could you not have been excising? could they not have been excising?