English verb conjugation
CAN PURCHASE

Regular verb: purchase - purchased - purchased

Affirmation

Simple form	V-ing form
I can purchase you can purchase he can purchase we can purchase you can purchase they can purchase	I can be purchasing you can be purchasing he can be purchasing we can be purchasing you can be purchasing they can be purchasing
Perfect	V-ing perfect
I can have purchased you can have purchased he can have purchased we can have purchased you can have purchased they can have purchased	I can have been purchasing you can have been purchasing he can have been purchasing we can have been purchasing you can have been purchasing they can have been purchasing

Negation

Simple form	V-ing form
I cannot purchase you cannot purchase he cannot purchase we cannot purchase you cannot purchase they cannot purchase	I cannot be purchasing you cannot be purchasing he cannot be purchasing we cannot be purchasing you cannot be purchasing they cannot be purchasing
Perfect	V-ing perfect
I cannot have purchased you cannot have purchased he cannot have purchased we cannot have purchased you cannot have purchased they cannot have purchased	I cannot have been purchasing you cannot have been purchasing he cannot have been purchasing we cannot have been purchasing you cannot have been purchasing they cannot have been purchasing

Interrogative form

Simple form	V-ing form
can I purchase? can you purchase? can he purchase? can we purchase? can you purchase? can they purchase?	can I be purchasing? can you be purchasing? can he be purchasing? can we be purchasing? can you be purchasing? can they be purchasing?
Perfect	V-ing perfect
can I have purchased? can you have purchased? can he have purchased? can we have purchased? can you have purchased? can they have purchased?	can I have been purchasing? can you have been purchasing? can he have been purchasing? can we have been purchasing? can you have been purchasing? can they have been purchasing?

Interro-negative form

Simple form	V-ing form
can I not purchase? can you not purchase? can he not purchase? can we not purchase? can you not purchase? can they not purchase?	can I not be purchasing? can you not be purchasing? can he not be purchasing? can we not be purchasing? can you not be purchasing? can they not be purchasing?
Perfect	V-ing perfect
can I not have purchased? can you not have purchased? can he not have purchased? can we not have purchased? can you not have purchased? can they not have purchased?	can I not have been purchasing? can you not have been purchasing? can he not have been purchasing? can we not have been purchasing? can you not have been purchasing? can they not have been purchasing?