English verb conjugation
CAN BUY

Irregular verb: buy - bought - bought

Affirmation

Simple form	V-ing form
I can buy you can buy he can buy we can buy you can buy they can buy	I can be buying you can be buying he can be buying we can be buying you can be buying they can be buying
Perfect	V-ing perfect
I can have bought you can have bought he can have bought we can have bought you can have bought they can have bought	I can have been buying you can have been buying he can have been buying we can have been buying you can have been buying they can have been buying

Negation

Simple form	V-ing form
I cannot buy you cannot buy he cannot buy we cannot buy you cannot buy they cannot buy	I cannot be buying you cannot be buying he cannot be buying we cannot be buying you cannot be buying they cannot be buying
Perfect	V-ing perfect
I cannot have bought you cannot have bought he cannot have bought we cannot have bought you cannot have bought they cannot have bought	I cannot have been buying you cannot have been buying he cannot have been buying we cannot have been buying you cannot have been buying they cannot have been buying

Interrogative form

Simple form	V-ing form
can I buy? can you buy? can he buy? can we buy? can you buy? can they buy?	can I be buying? can you be buying? can he be buying? can we be buying? can you be buying? can they be buying?
Perfect	V-ing perfect
can I have bought? can you have bought? can he have bought? can we have bought? can you have bought? can they have bought?	can I have been buying? can you have been buying? can he have been buying? can we have been buying? can you have been buying? can they have been buying?

Interro-negative form

Simple form	V-ing form
can I not buy? can you not buy? can he not buy? can we not buy? can you not buy? can they not buy?	can I not be buying? can you not be buying? can he not be buying? can we not be buying? can you not be buying? can they not be buying?
Perfect	V-ing perfect
can I not have bought? can you not have bought? can he not have bought? can we not have bought? can you not have bought? can they not have bought?	can I not have been buying? can you not have been buying? can he not have been buying? can we not have been buying? can you not have been buying? can they not have been buying?