English verb conjugation
COULD SPIFF

Regular verb: spiff - spiffed - spiffed

Affirmation

Simple form	V-ing form
I could spiff you could spiff he could spiff we could spiff you could spiff they could spiff	I could be spiffing you could be spiffing he could be spiffing we could be spiffing you could be spiffing they could be spiffing
Perfect	V-ing perfect
I could have spiffed you could have spiffed he could have spiffed we could have spiffed you could have spiffed they could have spiffed	I could have been spiffing you could have been spiffing he could have been spiffing we could have been spiffing you could have been spiffing they could have been spiffing

Negation

Simple form	V-ing form
I couldn't spiff you couldn't spiff he couldn't spiff we couldn't spiff you couldn't spiff they couldn't spiff	I couldn't be spiffing you couldn't be spiffing he couldn't be spiffing we couldn't be spiffing you couldn't be spiffing they couldn't be spiffing
Perfect	V-ing perfect
I couldn't have spiffed you couldn't have spiffed he couldn't have spiffed we couldn't have spiffed you couldn't have spiffed they couldn't have spiffed	I couldn't have been spiffing you couldn't have been spiffing he couldn't have been spiffing we couldn't have been spiffing you couldn't have been spiffing they couldn't have been spiffing

Interrogative form

Simple form	V-ing form
could I spiff? could you spiff? could he spiff? could we spiff? could you spiff? could they spiff?	could I be spiffing? could you be spiffing? could he be spiffing? could we be spiffing? could you be spiffing? could they be spiffing?
Perfect	V-ing perfect
could I have spiffed? could you have spiffed? could he have spiffed? could we have spiffed? could you have spiffed? could they have spiffed?	could I have been spiffing? could you have been spiffing? could he have been spiffing? could we have been spiffing? could you have been spiffing? could they have been spiffing?

Interro-negative form

Simple form	V-ing form
couldn't I spiff? couldn't you spiff? couldn't he spiff? couldn't we spiff? couldn't you spiff? couldn't they spiff?	couldn't I be spiffing? couldn't you be spiffing? couldn't he be spiffing? couldn't we be spiffing? couldn't you be spiffing? couldn't they be spiffing?
Perfect	V-ing perfect
couldn't I have spiffed? couldn't you have spiffed? couldn't he have spiffed? couldn't we have spiffed? couldn't you have spiffed? couldn't they have spiffed?	couldn't I have been spiffing? couldn't you have been spiffing? couldn't he have been spiffing? couldn't we have been spiffing? couldn't you have been spiffing? couldn't they have been spiffing?