English verb conjugation
COULD PUFF

Regular verb: puff - puffed - puffed

Affirmation

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

Negation

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

Interrogative form

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

Interro-negative form

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