English verb conjugation
COULD COST

Irregular verb: cost - cost - cost

Affirmation

Simple form	V-ing form
I could cost you could cost he could cost we could cost you could cost they could cost	I could be costing you could be costing he could be costing we could be costing you could be costing they could be costing
Perfect	V-ing perfect
I could have cost you could have cost he could have cost we could have cost you could have cost they could have cost	I could have been costing you could have been costing he could have been costing we could have been costing you could have been costing they could have been costing

Negation

Simple form	V-ing form
I could not cost you could not cost he could not cost we could not cost you could not cost they could not cost	I could not be costing you could not be costing he could not be costing we could not be costing you could not be costing they could not be costing
Perfect	V-ing perfect
I could not have cost you could not have cost he could not have cost we could not have cost you could not have cost they could not have cost	I could not have been costing you could not have been costing he could not have been costing we could not have been costing you could not have been costing they could not have been costing

Interrogative form

Simple form	V-ing form
could I cost? could you cost? could he cost? could we cost? could you cost? could they cost?	could I be costing? could you be costing? could he be costing? could we be costing? could you be costing? could they be costing?
Perfect	V-ing perfect
could I have cost? could you have cost? could he have cost? could we have cost? could you have cost? could they have cost?	could I have been costing? could you have been costing? could he have been costing? could we have been costing? could you have been costing? could they have been costing?

Interro-negative form

Simple form	V-ing form
could I not cost? could you not cost? could he not cost? could we not cost? could you not cost? could they not cost?	could I not be costing? could you not be costing? could he not be costing? could we not be costing? could you not be costing? could they not be costing?
Perfect	V-ing perfect
could I not have cost? could you not have cost? could he not have cost? could we not have cost? could you not have cost? could they not have cost?	could I not have been costing? could you not have been costing? could he not have been costing? could we not have been costing? could you not have been costing? could they not have been costing?