English verb conjugation
CAN CONCUSS

Regular verb: concuss - concussed - concussed

Affirmation

Simple form	V-ing form
I can concuss you can concuss she can concuss we can concuss you can concuss they can concuss	I can be concussing you can be concussing she can be concussing we can be concussing you can be concussing they can be concussing
Perfect	V-ing perfect
I can have concussed you can have concussed she can have concussed we can have concussed you can have concussed they can have concussed	I can have been concussing you can have been concussing she can have been concussing we can have been concussing you can have been concussing they can have been concussing

Negation

Simple form	V-ing form
I cannot concuss you cannot concuss she cannot concuss we cannot concuss you cannot concuss they cannot concuss	I cannot be concussing you cannot be concussing she cannot be concussing we cannot be concussing you cannot be concussing they cannot be concussing
Perfect	V-ing perfect
I cannot have concussed you cannot have concussed she cannot have concussed we cannot have concussed you cannot have concussed they cannot have concussed	I cannot have been concussing you cannot have been concussing she cannot have been concussing we cannot have been concussing you cannot have been concussing they cannot have been concussing

Interrogative form

Simple form	V-ing form
can I concuss? can you concuss? can she concuss? can we concuss? can you concuss? can they concuss?	can I be concussing? can you be concussing? can she be concussing? can we be concussing? can you be concussing? can they be concussing?
Perfect	V-ing perfect
can I have concussed? can you have concussed? can she have concussed? can we have concussed? can you have concussed? can they have concussed?	can I have been concussing? can you have been concussing? can she have been concussing? can we have been concussing? can you have been concussing? can they have been concussing?

Interro-negative form

Simple form	V-ing form
can I not concuss? can you not concuss? can she not concuss? can we not concuss? can you not concuss? can they not concuss?	can I not be concussing? can you not be concussing? can she not be concussing? can we not be concussing? can you not be concussing? can they not be concussing?
Perfect	V-ing perfect
can I not have concussed? can you not have concussed? can she not have concussed? can we not have concussed? can you not have concussed? can they not have concussed?	can I not have been concussing? can you not have been concussing? can she not have been concussing? can we not have been concussing? can you not have been concussing? can they not have been concussing?