English verb conjugation
COULD QUIZ

Regular verb: quiz - quizzed - quizzed

Affirmation

Simple form	V-ing form
I could quiz you could quiz he could quiz we could quiz you could quiz they could quiz	I could be quizzing you could be quizzing he could be quizzing we could be quizzing you could be quizzing they could be quizzing
Perfect	V-ing perfect
I could have quizzed you could have quizzed he could have quizzed we could have quizzed you could have quizzed they could have quizzed	I could have been quizzing you could have been quizzing he could have been quizzing we could have been quizzing you could have been quizzing they could have been quizzing

Negation

Simple form	V-ing form
I couldn't quiz you couldn't quiz he couldn't quiz we couldn't quiz you couldn't quiz they couldn't quiz	I couldn't be quizzing you couldn't be quizzing he couldn't be quizzing we couldn't be quizzing you couldn't be quizzing they couldn't be quizzing
Perfect	V-ing perfect
I couldn't have quizzed you couldn't have quizzed he couldn't have quizzed we couldn't have quizzed you couldn't have quizzed they couldn't have quizzed	I couldn't have been quizzing you couldn't have been quizzing he couldn't have been quizzing we couldn't have been quizzing you couldn't have been quizzing they couldn't have been quizzing

Interrogative form

Simple form	V-ing form
could I quiz? could you quiz? could he quiz? could we quiz? could you quiz? could they quiz?	could I be quizzing? could you be quizzing? could he be quizzing? could we be quizzing? could you be quizzing? could they be quizzing?
Perfect	V-ing perfect
could I have quizzed? could you have quizzed? could he have quizzed? could we have quizzed? could you have quizzed? could they have quizzed?	could I have been quizzing? could you have been quizzing? could he have been quizzing? could we have been quizzing? could you have been quizzing? could they have been quizzing?

Interro-negative form

Simple form	V-ing form
couldn't I quiz? couldn't you quiz? couldn't he quiz? couldn't we quiz? couldn't you quiz? couldn't they quiz?	couldn't I be quizzing? couldn't you be quizzing? couldn't he be quizzing? couldn't we be quizzing? couldn't you be quizzing? couldn't they be quizzing?
Perfect	V-ing perfect
couldn't I have quizzed? couldn't you have quizzed? couldn't he have quizzed? couldn't we have quizzed? couldn't you have quizzed? couldn't they have quizzed?	couldn't I have been quizzing? couldn't you have been quizzing? couldn't he have been quizzing? couldn't we have been quizzing? couldn't you have been quizzing? couldn't they have been quizzing?