English verb conjugation
COULD RETESTIFY

Regular verb: retestify - retestified - retestified

Affirmation

Simple form	V-ing form
I could retestify you could retestify he could retestify we could retestify you could retestify they could retestify	I could be retestifying you could be retestifying he could be retestifying we could be retestifying you could be retestifying they could be retestifying
Perfect	V-ing perfect
I could have retestified you could have retestified he could have retestified we could have retestified you could have retestified they could have retestified	I could have been retestifying you could have been retestifying he could have been retestifying we could have been retestifying you could have been retestifying they could have been retestifying

Negation

Simple form	V-ing form
I could not retestify you could not retestify he could not retestify we could not retestify you could not retestify they could not retestify	I could not be retestifying you could not be retestifying he could not be retestifying we could not be retestifying you could not be retestifying they could not be retestifying
Perfect	V-ing perfect
I could not have retestified you could not have retestified he could not have retestified we could not have retestified you could not have retestified they could not have retestified	I could not have been retestifying you could not have been retestifying he could not have been retestifying we could not have been retestifying you could not have been retestifying they could not have been retestifying

Interrogative form

Simple form	V-ing form
could I retestify? could you retestify? could he retestify? could we retestify? could you retestify? could they retestify?	could I be retestifying? could you be retestifying? could he be retestifying? could we be retestifying? could you be retestifying? could they be retestifying?
Perfect	V-ing perfect
could I have retestified? could you have retestified? could he have retestified? could we have retestified? could you have retestified? could they have retestified?	could I have been retestifying? could you have been retestifying? could he have been retestifying? could we have been retestifying? could you have been retestifying? could they have been retestifying?

Interro-negative form

Simple form	V-ing form
could I not retestify? could you not retestify? could he not retestify? could we not retestify? could you not retestify? could they not retestify?	could I not be retestifying? could you not be retestifying? could he not be retestifying? could we not be retestifying? could you not be retestifying? could they not be retestifying?
Perfect	V-ing perfect
could I not have retestified? could you not have retestified? could he not have retestified? could we not have retestified? could you not have retestified? could they not have retestified?	could I not have been retestifying? could you not have been retestifying? could he not have been retestifying? could we not have been retestifying? could you not have been retestifying? could they not have been retestifying?