English verb conjugation
CAN PUFF

Regular verb: puff - puffed - puffed

Affirmation

Simple form	V-ing form
I can puff you can puff he can puff we can puff you can puff they can puff	I can be puffing you can be puffing he can be puffing we can be puffing you can be puffing they can be puffing
Perfect	V-ing perfect
I can have puffed you can have puffed he can have puffed we can have puffed you can have puffed they can have puffed	I can have been puffing you can have been puffing he can have been puffing we can have been puffing you can have been puffing they can have been puffing

Negation

Simple form	V-ing form
I can't puff you can't puff he can't puff we can't puff you can't puff they can't puff	I can't be puffing you can't be puffing he can't be puffing we can't be puffing you can't be puffing they can't be puffing
Perfect	V-ing perfect
I can't have puffed you can't have puffed he can't have puffed we can't have puffed you can't have puffed they can't have puffed	I can't have been puffing you can't have been puffing he can't have been puffing we can't have been puffing you can't have been puffing they can't have been puffing

Interrogative form

Simple form	V-ing form
can I puff? can you puff? can he puff? can we puff? can you puff? can they puff?	can I be puffing? can you be puffing? can he be puffing? can we be puffing? can you be puffing? can they be puffing?
Perfect	V-ing perfect
can I have puffed? can you have puffed? can he have puffed? can we have puffed? can you have puffed? can they have puffed?	can I have been puffing? can you have been puffing? can he have been puffing? can we have been puffing? can you have been puffing? can they have been puffing?

Interro-negative form

Simple form	V-ing form
can't I puff? can't you puff? can't he puff? can't we puff? can't you puff? can't they puff?	can't I be puffing? can't you be puffing? can't he be puffing? can't we be puffing? can't you be puffing? can't they be puffing?
Perfect	V-ing perfect
can't I have puffed? can't you have puffed? can't he have puffed? can't we have puffed? can't you have puffed? can't they have puffed?	can't I have been puffing? can't you have been puffing? can't he have been puffing? can't we have been puffing? can't you have been puffing? can't they have been puffing?