could question
Regular verb: question - questioned- questioned

Affirmation 	
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I could question
you could question
she could question
we could question
you could question
they could question 	I could be questioning
you could be questioning
she could be questioning
we could be questioning
you could be questioning
they could be questioning	I could have questioned
you could have questioned
she could have questioned
we could have questioned
you could have questioned
they could have questioned	I could have been questioning
you could have been questioning
she could have been questioning
we could have been questioning
you could have been questioning
they could have been questioning	

Negation 	
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I couldn't question
you couldn't question
she couldn't question
we couldn't question
you couldn't question
they couldn't question 	I couldn't be questioning
you couldn't be questioning
she couldn't be questioning
we couldn't be questioning
you couldn't be questioning
they couldn't be questioning	I couldn't have questioned
you couldn't have questioned
she couldn't have questioned
we couldn't have questioned
you couldn't have questioned
they couldn't have questioned	I couldn't have been questioning
you couldn't have been questioning
she couldn't have been questioning
we couldn't have been questioning
you couldn't have been questioning
they couldn't have been questioning	

Interrogative form 	
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could I question?
could you question?
could she question?
could we question?
could you question?
could they question? 	could I be questioning?
could you be questioning?
could she be questioning?
could we be questioning?
could you be questioning?
could they be questioning? 	could I have questioned?
could you have questioned?
could she have questioned?
could we have questioned?
could you have questioned?
could they have questioned? 	could I have been questioning?
could you have been questioning?
could she have been questioning?
could we have been questioning?
could you have been questioning?
could they have been questioning? 	

Interro-negative form 	
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couldn't I question?
couldn't you question?
couldn't she question?
couldn't we question?
couldn't you question?
couldn't they question? 	couldn't I be questioning?
couldn't you be questioning?
couldn't she be questioning?
couldn't we be questioning?
couldn't you be questioning?
couldn't they be questioning? 	couldn't I have questioned?
couldn't you have questioned?
couldn't she have questioned?
couldn't we have questioned?
couldn't you have questioned?
couldn't they have questioned? 	couldn't I have been questioning?
couldn't you have been questioning?
couldn't she have been questioning?
couldn't we have been questioning?
couldn't you have been questioning?
couldn't they have been questioning?