English verb conjugation
CAN BIFF

Regular verb: biff - biffed - biffed

Affirmation

Simple form	V-ing form
I can biff you can biff she can biff we can biff you can biff they can biff	I can be biffing you can be biffing she can be biffing we can be biffing you can be biffing they can be biffing
Perfect	V-ing perfect
I can have biffed you can have biffed she can have biffed we can have biffed you can have biffed they can have biffed	I can have been biffing you can have been biffing she can have been biffing we can have been biffing you can have been biffing they can have been biffing

Negation

Simple form	V-ing form
I cannot biff you cannot biff she cannot biff we cannot biff you cannot biff they cannot biff	I cannot be biffing you cannot be biffing she cannot be biffing we cannot be biffing you cannot be biffing they cannot be biffing
Perfect	V-ing perfect
I cannot have biffed you cannot have biffed she cannot have biffed we cannot have biffed you cannot have biffed they cannot have biffed	I cannot have been biffing you cannot have been biffing she cannot have been biffing we cannot have been biffing you cannot have been biffing they cannot have been biffing

Interrogative form

Simple form	V-ing form
can I biff? can you biff? can she biff? can we biff? can you biff? can they biff?	can I be biffing? can you be biffing? can she be biffing? can we be biffing? can you be biffing? can they be biffing?
Perfect	V-ing perfect
can I have biffed? can you have biffed? can she have biffed? can we have biffed? can you have biffed? can they have biffed?	can I have been biffing? can you have been biffing? can she have been biffing? can we have been biffing? can you have been biffing? can they have been biffing?

Interro-negative form

Simple form	V-ing form
can I not biff? can you not biff? can she not biff? can we not biff? can you not biff? can they not biff?	can I not be biffing? can you not be biffing? can she not be biffing? can we not be biffing? can you not be biffing? can they not be biffing?
Perfect	V-ing perfect
can I not have biffed? can you not have biffed? can she not have biffed? can we not have biffed? can you not have biffed? can they not have biffed?	can I not have been biffing? can you not have been biffing? can she not have been biffing? can we not have been biffing? can you not have been biffing? can they not have been biffing?