Conjugaison du verbe anglais COULD CERTIFY

I could certify
you could certify
he could certify
we could certify
you could certify
they could certify

I could be certifying
you could be certifying
he could be certifying
we could be certifying
you could be certifying
they could be certifying

I could have certified
you could have certified
he could have certified
we could have certified
you could have certified
they could have certified

I could have been certifying
you could have been certifying
he could have been certifying
we could have been certifying
you could have been certifying
they could have been certifying

I could not certify
you could not certify
he could not certify
we could not certify
you could not certify
they could not certify

I could not be certifying
you could not be certifying
he could not be certifying
we could not be certifying
you could not be certifying
they could not be certifying

I could not have certified
you could not have certified
he could not have certified
we could not have certified
you could not have certified
they could not have certified

I could not have been certifying
you could not have been certifying
he could not have been certifying
we could not have been certifying
you could not have been certifying
they could not have been certifying

could I certify?
could you certify?
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could you be certifying?
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could you be certifying?
could they be certifying?

could I have certified?
could you have certified?
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could they have certified?

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could you have been certifying?
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could they have been certifying?

could I not certify?
could you not certify?
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could they not certify?

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could you not be certifying?
could he not be certifying?
could we not be certifying?
could you not be certifying?
could they not be certifying?

could I not have certified?
could you not have certified?
could he not have certified?
could we not have certified?
could you not have certified?
could they not have certified?

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could you not have been certifying?
could he not have been certifying?
could we not have been certifying?
could you not have been certifying?
could they not have been certifying?