English verb conjugation
COULD YAK

Regular verb: yak - yaked - yaked

Affirmation

Simple form	V-ing form
I could yak you could yak he could yak we could yak you could yak they could yak	I could be yaking you could be yaking he could be yaking we could be yaking you could be yaking they could be yaking
Perfect	V-ing perfect
I could have yaked you could have yaked he could have yaked we could have yaked you could have yaked they could have yaked	I could have been yaking you could have been yaking he could have been yaking we could have been yaking you could have been yaking they could have been yaking

Negation

Simple form	V-ing form
I could not yak you could not yak he could not yak we could not yak you could not yak they could not yak	I could not be yaking you could not be yaking he could not be yaking we could not be yaking you could not be yaking they could not be yaking
Perfect	V-ing perfect
I could not have yaked you could not have yaked he could not have yaked we could not have yaked you could not have yaked they could not have yaked	I could not have been yaking you could not have been yaking he could not have been yaking we could not have been yaking you could not have been yaking they could not have been yaking

Interrogative form

Simple form	V-ing form
could I yak? could you yak? could he yak? could we yak? could you yak? could they yak?	could I be yaking? could you be yaking? could he be yaking? could we be yaking? could you be yaking? could they be yaking?
Perfect	V-ing perfect
could I have yaked? could you have yaked? could he have yaked? could we have yaked? could you have yaked? could they have yaked?	could I have been yaking? could you have been yaking? could he have been yaking? could we have been yaking? could you have been yaking? could they have been yaking?

Interro-negative form

Simple form	V-ing form
could I not yak? could you not yak? could he not yak? could we not yak? could you not yak? could they not yak?	could I not be yaking? could you not be yaking? could he not be yaking? could we not be yaking? could you not be yaking? could they not be yaking?
Perfect	V-ing perfect
could I not have yaked? could you not have yaked? could he not have yaked? could we not have yaked? could you not have yaked? could they not have yaked?	could I not have been yaking? could you not have been yaking? could he not have been yaking? could we not have been yaking? could you not have been yaking? could they not have been yaking?