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 couldn't shudder
you couldn't shudder
she couldn't shudder
we couldn't shudder
you couldn't shudder
they couldn't shudder 	I couldn't be shuddering
you couldn't be shuddering
she couldn't be shuddering
we couldn't be shuddering
you couldn't be shuddering
they couldn't be shuddering	I couldn't have shuddered
you couldn't have shuddered
she couldn't have shuddered
we couldn't have shuddered
you couldn't have shuddered
they couldn't have shuddered	I couldn't have been shuddering
you couldn't have been shuddering
she couldn't have been shuddering
we couldn't have been shuddering
you couldn't have been shuddering
they couldn't 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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couldn't I shudder?
couldn't you shudder?
couldn't she shudder?
couldn't we shudder?
couldn't you shudder?
couldn't they shudder? 	couldn't I be shuddering?
couldn't you be shuddering?
couldn't she be shuddering?
couldn't we be shuddering?
couldn't you be shuddering?
couldn't they be shuddering? 	couldn't I have shuddered?
couldn't you have shuddered?
couldn't she have shuddered?
couldn't we have shuddered?
couldn't you have shuddered?
couldn't they have shuddered? 	couldn't I have been shuddering?
couldn't you have been shuddering?
couldn't she have been shuddering?
couldn't we have been shuddering?
couldn't you have been shuddering?
couldn't they have been shuddering?