could shudder
Regular verb: shudder - shuddered- shuddered

Affirmation 	
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I could shudder
you could shudder
she could shudder
we could shudder
you could shudder
they could shudder 	I could be shuddering
you could be shuddering
she could be shuddering
we could be shuddering
you could be shuddering
they could be shuddering	I could have shuddered
you could have shuddered
she could have shuddered
we could have shuddered
you could have shuddered
they could have shuddered	I could have been shuddering
you could have been shuddering
she could have been shuddering
we could have been shuddering
you could have been shuddering
they could have been shuddering	

Negation 	
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I could not shudder
you could not shudder
she could not shudder
we could not shudder
you could not shudder
they could not shudder 	I could not be shuddering
you could not be shuddering
she could not be shuddering
we could not be shuddering
you could not be shuddering
they could not be shuddering	I could not have shuddered
you could not have shuddered
she could not have shuddered
we could not have shuddered
you could not have shuddered
they could not have shuddered	I could not have been shuddering
you could not have been shuddering
she could not have been shuddering
we could not have been shuddering
you could not have been shuddering
they could not have been shuddering	

Interrogative form 	
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could I shudder?
could you shudder?
could she shudder?
could we shudder?
could you shudder?
could they shudder? 	could I be shuddering?
could you be shuddering?
could she be shuddering?
could we be shuddering?
could you be shuddering?
could they be shuddering? 	could I have shuddered?
could you have shuddered?
could she have shuddered?
could we have shuddered?
could you have shuddered?
could they have shuddered? 	could I have been shuddering?
could you have been shuddering?
could she have been shuddering?
could we have been shuddering?
could you have been shuddering?
could they have been shuddering? 	

Interro-negative form 	
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could I not shudder?
could you not shudder?
could she not shudder?
could we not shudder?
could you not shudder?
could they not shudder? 	could I not be shuddering?
could you not be shuddering?
could she not be shuddering?
could we not be shuddering?
could you not be shuddering?
could they not be shuddering? 	could I not have shuddered?
could you not have shuddered?
could she not have shuddered?
could we not have shuddered?
could you not have shuddered?
could they not have shuddered? 	could I not have been shuddering?
could you not have been shuddering?
could she not have been shuddering?
could we not have been shuddering?
could you not have been shuddering?
could they not have been shuddering?