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 couldn't retestify you couldn't retestify he couldn't retestify we couldn't retestify you couldn't retestify they couldn't retestify	I couldn't be retestifying you couldn't be retestifying he couldn't be retestifying we couldn't be retestifying you couldn't be retestifying they couldn't be retestifying
Perfect	V-ing perfect
I couldn't have retestified you couldn't have retestified he couldn't have retestified we couldn't have retestified you couldn't have retestified they couldn't have retestified	I couldn't have been retestifying you couldn't have been retestifying he couldn't have been retestifying we couldn't have been retestifying you couldn't have been retestifying they couldn't 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
couldn't I retestify? couldn't you retestify? couldn't he retestify? couldn't we retestify? couldn't you retestify? couldn't they retestify?	couldn't I be retestifying? couldn't you be retestifying? couldn't he be retestifying? couldn't we be retestifying? couldn't you be retestifying? couldn't they be retestifying?
Perfect	V-ing perfect
couldn't I have retestified? couldn't you have retestified? couldn't he have retestified? couldn't we have retestified? couldn't you have retestified? couldn't they have retestified?	couldn't I have been retestifying? couldn't you have been retestifying? couldn't he have been retestifying? couldn't we have been retestifying? couldn't you have been retestifying? couldn't they have been retestifying?