I can base you can base he can base we can base you can base they can base
V-ing form
I can be basing you can be basing he can be basing we can be basing you can be basing they can be basing
Perfect
I can have based you can have based he can have based we can have based you can have based they can have based
V-ing perfect
I can have been basing you can have been basing he can have been basing we can have been basing you can have been basing they can have been basing
Negation
Simple form
I cannot base you cannot base he cannot base we cannot base you cannot base they cannot base
V-ing form
I cannot be basing you cannot be basing he cannot be basing we cannot be basing you cannot be basing they cannot be basing
Perfect
I cannot have based you cannot have based he cannot have based we cannot have based you cannot have based they cannot have based
V-ing perfect
I cannot have been basing you cannot have been basing he cannot have been basing we cannot have been basing you cannot have been basing they cannot have been basing
Interrogative form
Simple form
can I base? can you base? can he base? can we base? can you base? can they base?
V-ing form
can I be basing? can you be basing? can he be basing? can we be basing? can you be basing? can they be basing?
Perfect
can I have based? can you have based? can he have based? can we have based? can you have based? can they have based?
V-ing perfect
can I have been basing? can you have been basing? can he have been basing? can we have been basing? can you have been basing? can they have been basing?
Interro-negative form
Simple form
can I not base? can you not base? can he not base? can we not base? can you not base? can they not base?
V-ing form
can I not be basing? can you not be basing? can he not be basing? can we not be basing? can you not be basing? can they not be basing?
Perfect
can I not have based? can you not have based? can he not have based? can we not have based? can you not have based? can they not have based?
V-ing perfect
can I not have been basing? can you not have been basing? can he not have been basing? can we not have been basing? can you not have been basing? can they not have been basing?