could decrease
Verbo regular: decrease - decreased- decreased

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could decrease
you could decrease
he could decrease
we could decrease
you could decrease
they could decrease 	I could be decreasing
you could be decreasing
he could be decreasing
we could be decreasing
you could be decreasing
they could be decreasing	I could have decreased
you could have decreased
he could have decreased
we could have decreased
you could have decreased
they could have decreased	I could have been decreasing
you could have been decreasing
he could have been decreasing
we could have been decreasing
you could have been decreasing
they could have been decreasing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't decrease
you couldn't decrease
he couldn't decrease
we couldn't decrease
you couldn't decrease
they couldn't decrease 	I couldn't be decreasing
you couldn't be decreasing
he couldn't be decreasing
we couldn't be decreasing
you couldn't be decreasing
they couldn't be decreasing	I couldn't have decreased
you couldn't have decreased
he couldn't have decreased
we couldn't have decreased
you couldn't have decreased
they couldn't have decreased	I couldn't have been decreasing
you couldn't have been decreasing
he couldn't have been decreasing
we couldn't have been decreasing
you couldn't have been decreasing
they couldn't have been decreasing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I decrease?
could you decrease?
could he decrease?
could we decrease?
could you decrease?
could they decrease? 	could I be decreasing?
could you be decreasing?
could he be decreasing?
could we be decreasing?
could you be decreasing?
could they be decreasing? 	could I have decreased?
could you have decreased?
could he have decreased?
could we have decreased?
could you have decreased?
could they have decreased? 	could I have been decreasing?
could you have been decreasing?
could he have been decreasing?
could we have been decreasing?
could you have been decreasing?
could they have been decreasing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I decrease?
couldn't you decrease?
couldn't he decrease?
couldn't we decrease?
couldn't you decrease?
couldn't they decrease? 	couldn't I be decreasing?
couldn't you be decreasing?
couldn't he be decreasing?
couldn't we be decreasing?
couldn't you be decreasing?
couldn't they be decreasing? 	couldn't I have decreased?
couldn't you have decreased?
couldn't he have decreased?
couldn't we have decreased?
couldn't you have decreased?
couldn't they have decreased? 	couldn't I have been decreasing?
couldn't you have been decreasing?
couldn't he have been decreasing?
couldn't we have been decreasing?
couldn't you have been decreasing?
couldn't they have been decreasing?