could quiz
Regular verb: quiz - quizzed- quizzed

Affirmation 	
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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	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 	
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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	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 	
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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? 	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 	
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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? 	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?