English verb conjugation
COULD CHECKER

Regular verb: checker - checkered - checkered

Affirmation

Simple form	V-ing form
I could checker you could checker she could checker we could checker you could checker they could checker	I could be checkering you could be checkering she could be checkering we could be checkering you could be checkering they could be checkering
Perfect	V-ing perfect
I could have checkered you could have checkered she could have checkered we could have checkered you could have checkered they could have checkered	I could have been checkering you could have been checkering she could have been checkering we could have been checkering you could have been checkering they could have been checkering

Negation

Simple form	V-ing form
I couldn't checker you couldn't checker she couldn't checker we couldn't checker you couldn't checker they couldn't checker	I couldn't be checkering you couldn't be checkering she couldn't be checkering we couldn't be checkering you couldn't be checkering they couldn't be checkering
Perfect	V-ing perfect
I couldn't have checkered you couldn't have checkered she couldn't have checkered we couldn't have checkered you couldn't have checkered they couldn't have checkered	I couldn't have been checkering you couldn't have been checkering she couldn't have been checkering we couldn't have been checkering you couldn't have been checkering they couldn't have been checkering

Interrogative form

Simple form	V-ing form
could I checker? could you checker? could she checker? could we checker? could you checker? could they checker?	could I be checkering? could you be checkering? could she be checkering? could we be checkering? could you be checkering? could they be checkering?
Perfect	V-ing perfect
could I have checkered? could you have checkered? could she have checkered? could we have checkered? could you have checkered? could they have checkered?	could I have been checkering? could you have been checkering? could she have been checkering? could we have been checkering? could you have been checkering? could they have been checkering?

Interro-negative form

Simple form	V-ing form
couldn't I checker? couldn't you checker? couldn't she checker? couldn't we checker? couldn't you checker? couldn't they checker?	couldn't I be checkering? couldn't you be checkering? couldn't she be checkering? couldn't we be checkering? couldn't you be checkering? couldn't they be checkering?
Perfect	V-ing perfect
couldn't I have checkered? couldn't you have checkered? couldn't she have checkered? couldn't we have checkered? couldn't you have checkered? couldn't they have checkered?	couldn't I have been checkering? couldn't you have been checkering? couldn't she have been checkering? couldn't we have been checkering? couldn't you have been checkering? couldn't they have been checkering?