could upend
Regular verb: upend - upended- upended

Affirmation 	
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I could upend
you could upend
he could upend
we could upend
you could upend
they could upend 	I could be upending
you could be upending
he could be upending
we could be upending
you could be upending
they could be upending	I could have upended
you could have upended
he could have upended
we could have upended
you could have upended
they could have upended	I could have been upending
you could have been upending
he could have been upending
we could have been upending
you could have been upending
they could have been upending	

Negation 	
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I couldn't upend
you couldn't upend
he couldn't upend
we couldn't upend
you couldn't upend
they couldn't upend 	I couldn't be upending
you couldn't be upending
he couldn't be upending
we couldn't be upending
you couldn't be upending
they couldn't be upending	I couldn't have upended
you couldn't have upended
he couldn't have upended
we couldn't have upended
you couldn't have upended
they couldn't have upended	I couldn't have been upending
you couldn't have been upending
he couldn't have been upending
we couldn't have been upending
you couldn't have been upending
they couldn't have been upending	

Interrogative form 	
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could I upend?
could you upend?
could he upend?
could we upend?
could you upend?
could they upend? 	could I be upending?
could you be upending?
could he be upending?
could we be upending?
could you be upending?
could they be upending? 	could I have upended?
could you have upended?
could he have upended?
could we have upended?
could you have upended?
could they have upended? 	could I have been upending?
could you have been upending?
could he have been upending?
could we have been upending?
could you have been upending?
could they have been upending? 	

Interro-negative form 	
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couldn't I upend?
couldn't you upend?
couldn't he upend?
couldn't we upend?
couldn't you upend?
couldn't they upend? 	couldn't I be upending?
couldn't you be upending?
couldn't he be upending?
couldn't we be upending?
couldn't you be upending?
couldn't they be upending? 	couldn't I have upended?
couldn't you have upended?
couldn't he have upended?
couldn't we have upended?
couldn't you have upended?
couldn't they have upended? 	couldn't I have been upending?
couldn't you have been upending?
couldn't he have been upending?
couldn't we have been upending?
couldn't you have been upending?
couldn't they have been upending?