could extinguish
Verbo regular: extinguish - extinguished- extinguished

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could extinguish
you could extinguish
he could extinguish
we could extinguish
you could extinguish
they could extinguish 	I could be extinguishing
you could be extinguishing
he could be extinguishing
we could be extinguishing
you could be extinguishing
they could be extinguishing	I could have extinguished
you could have extinguished
he could have extinguished
we could have extinguished
you could have extinguished
they could have extinguished	I could have been extinguishing
you could have been extinguishing
he could have been extinguishing
we could have been extinguishing
you could have been extinguishing
they could have been extinguishing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't extinguish
you couldn't extinguish
he couldn't extinguish
we couldn't extinguish
you couldn't extinguish
they couldn't extinguish 	I couldn't be extinguishing
you couldn't be extinguishing
he couldn't be extinguishing
we couldn't be extinguishing
you couldn't be extinguishing
they couldn't be extinguishing	I couldn't have extinguished
you couldn't have extinguished
he couldn't have extinguished
we couldn't have extinguished
you couldn't have extinguished
they couldn't have extinguished	I couldn't have been extinguishing
you couldn't have been extinguishing
he couldn't have been extinguishing
we couldn't have been extinguishing
you couldn't have been extinguishing
they couldn't have been extinguishing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I extinguish?
could you extinguish?
could he extinguish?
could we extinguish?
could you extinguish?
could they extinguish? 	could I be extinguishing?
could you be extinguishing?
could he be extinguishing?
could we be extinguishing?
could you be extinguishing?
could they be extinguishing? 	could I have extinguished?
could you have extinguished?
could he have extinguished?
could we have extinguished?
could you have extinguished?
could they have extinguished? 	could I have been extinguishing?
could you have been extinguishing?
could he have been extinguishing?
could we have been extinguishing?
could you have been extinguishing?
could they have been extinguishing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I extinguish?
couldn't you extinguish?
couldn't he extinguish?
couldn't we extinguish?
couldn't you extinguish?
couldn't they extinguish? 	couldn't I be extinguishing?
couldn't you be extinguishing?
couldn't he be extinguishing?
couldn't we be extinguishing?
couldn't you be extinguishing?
couldn't they be extinguishing? 	couldn't I have extinguished?
couldn't you have extinguished?
couldn't he have extinguished?
couldn't we have extinguished?
couldn't you have extinguished?
couldn't they have extinguished? 	couldn't I have been extinguishing?
couldn't you have been extinguishing?
couldn't he have been extinguishing?
couldn't we have been extinguishing?
couldn't you have been extinguishing?
couldn't they have been extinguishing?