could whistle
Verbo regular: whistle - whistled- whistled

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could whistle
you could whistle
he could whistle
we could whistle
you could whistle
they could whistle 	I could be whistling
you could be whistling
he could be whistling
we could be whistling
you could be whistling
they could be whistling	I could have whistled
you could have whistled
he could have whistled
we could have whistled
you could have whistled
they could have whistled	I could have been whistling
you could have been whistling
he could have been whistling
we could have been whistling
you could have been whistling
they could have been whistling	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not whistle
you could not whistle
he could not whistle
we could not whistle
you could not whistle
they could not whistle 	I could not be whistling
you could not be whistling
he could not be whistling
we could not be whistling
you could not be whistling
they could not be whistling	I could not have whistled
you could not have whistled
he could not have whistled
we could not have whistled
you could not have whistled
they could not have whistled	I could not have been whistling
you could not have been whistling
he could not have been whistling
we could not have been whistling
you could not have been whistling
they could not have been whistling	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I whistle?
could you whistle?
could he whistle?
could we whistle?
could you whistle?
could they whistle? 	could I be whistling?
could you be whistling?
could he be whistling?
could we be whistling?
could you be whistling?
could they be whistling? 	could I have whistled?
could you have whistled?
could he have whistled?
could we have whistled?
could you have whistled?
could they have whistled? 	could I have been whistling?
could you have been whistling?
could he have been whistling?
could we have been whistling?
could you have been whistling?
could they have been whistling? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not whistle?
could you not whistle?
could he not whistle?
could we not whistle?
could you not whistle?
could they not whistle? 	could I not be whistling?
could you not be whistling?
could he not be whistling?
could we not be whistling?
could you not be whistling?
could they not be whistling? 	could I not have whistled?
could you not have whistled?
could he not have whistled?
could we not have whistled?
could you not have whistled?
could they not have whistled? 	could I not have been whistling?
could you not have been whistling?
could he not have been whistling?
could we not have been whistling?
could you not have been whistling?
could they not have been whistling?