could vary
Verbo regular: vary - varied- varied

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could vary
you could vary
he could vary
we could vary
you could vary
they could vary 	I could be varying
you could be varying
he could be varying
we could be varying
you could be varying
they could be varying	I could have varied
you could have varied
he could have varied
we could have varied
you could have varied
they could have varied	I could have been varying
you could have been varying
he could have been varying
we could have been varying
you could have been varying
they could have been varying	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not vary
you could not vary
he could not vary
we could not vary
you could not vary
they could not vary 	I could not be varying
you could not be varying
he could not be varying
we could not be varying
you could not be varying
they could not be varying	I could not have varied
you could not have varied
he could not have varied
we could not have varied
you could not have varied
they could not have varied	I could not have been varying
you could not have been varying
he could not have been varying
we could not have been varying
you could not have been varying
they could not have been varying	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I vary?
could you vary?
could he vary?
could we vary?
could you vary?
could they vary? 	could I be varying?
could you be varying?
could he be varying?
could we be varying?
could you be varying?
could they be varying? 	could I have varied?
could you have varied?
could he have varied?
could we have varied?
could you have varied?
could they have varied? 	could I have been varying?
could you have been varying?
could he have been varying?
could we have been varying?
could you have been varying?
could they have been varying? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not vary?
could you not vary?
could he not vary?
could we not vary?
could you not vary?
could they not vary? 	could I not be varying?
could you not be varying?
could he not be varying?
could we not be varying?
could you not be varying?
could they not be varying? 	could I not have varied?
could you not have varied?
could he not have varied?
could we not have varied?
could you not have varied?
could they not have varied? 	could I not have been varying?
could you not have been varying?
could he not have been varying?
could we not have been varying?
could you not have been varying?
could they not have been varying?