could decrease
Verbo regular: decrease - decreased- decreased

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could decrease
you could decrease
she could decrease
we could decrease
you could decrease
they could decrease 	I could be decreasing
you could be decreasing
she could be decreasing
we could be decreasing
you could be decreasing
they could be decreasing	I could have decreased
you could have decreased
she 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
she could have been decreasing
we could have been decreasing
you could have been decreasing
they could have been decreasing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could not decrease
you could not decrease
she could not decrease
we could not decrease
you could not decrease
they could not decrease 	I could not be decreasing
you could not be decreasing
she could not be decreasing
we could not be decreasing
you could not be decreasing
they could not be decreasing	I could not have decreased
you could not have decreased
she could not have decreased
we could not have decreased
you could not have decreased
they could not have decreased	I could not have been decreasing
you could not have been decreasing
she could not have been decreasing
we could not have been decreasing
you could not have been decreasing
they could not have been decreasing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I decrease?
could you decrease?
could she decrease?
could we decrease?
could you decrease?
could they decrease? 	could I be decreasing?
could you be decreasing?
could she be decreasing?
could we be decreasing?
could you be decreasing?
could they be decreasing? 	could I have decreased?
could you have decreased?
could she 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 she have been decreasing?
could we have been decreasing?
could you have been decreasing?
could they have been decreasing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I not decrease?
could you not decrease?
could she not decrease?
could we not decrease?
could you not decrease?
could they not decrease? 	could I not be decreasing?
could you not be decreasing?
could she not be decreasing?
could we not be decreasing?
could you not be decreasing?
could they not be decreasing? 	could I not have decreased?
could you not have decreased?
could she not have decreased?
could we not have decreased?
could you not have decreased?
could they not have decreased? 	could I not have been decreasing?
could you not have been decreasing?
could she not have been decreasing?
could we not have been decreasing?
could you not have been decreasing?
could they not have been decreasing?