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