could interchange
Verbo regular: interchange - interchanged- interchanged

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could interchange
you could interchange
he could interchange
we could interchange
you could interchange
they could interchange 	I could be interchanging
you could be interchanging
he could be interchanging
we could be interchanging
you could be interchanging
they could be interchanging	I could have interchanged
you could have interchanged
he could have interchanged
we could have interchanged
you could have interchanged
they could have interchanged	I could have been interchanging
you could have been interchanging
he could have been interchanging
we could have been interchanging
you could have been interchanging
they could have been interchanging	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't interchange
you couldn't interchange
he couldn't interchange
we couldn't interchange
you couldn't interchange
they couldn't interchange 	I couldn't be interchanging
you couldn't be interchanging
he couldn't be interchanging
we couldn't be interchanging
you couldn't be interchanging
they couldn't be interchanging	I couldn't have interchanged
you couldn't have interchanged
he couldn't have interchanged
we couldn't have interchanged
you couldn't have interchanged
they couldn't have interchanged	I couldn't have been interchanging
you couldn't have been interchanging
he couldn't have been interchanging
we couldn't have been interchanging
you couldn't have been interchanging
they couldn't have been interchanging	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I interchange?
could you interchange?
could he interchange?
could we interchange?
could you interchange?
could they interchange? 	could I be interchanging?
could you be interchanging?
could he be interchanging?
could we be interchanging?
could you be interchanging?
could they be interchanging? 	could I have interchanged?
could you have interchanged?
could he have interchanged?
could we have interchanged?
could you have interchanged?
could they have interchanged? 	could I have been interchanging?
could you have been interchanging?
could he have been interchanging?
could we have been interchanging?
could you have been interchanging?
could they have been interchanging? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I interchange?
couldn't you interchange?
couldn't he interchange?
couldn't we interchange?
couldn't you interchange?
couldn't they interchange? 	couldn't I be interchanging?
couldn't you be interchanging?
couldn't he be interchanging?
couldn't we be interchanging?
couldn't you be interchanging?
couldn't they be interchanging? 	couldn't I have interchanged?
couldn't you have interchanged?
couldn't he have interchanged?
couldn't we have interchanged?
couldn't you have interchanged?
couldn't they have interchanged? 	couldn't I have been interchanging?
couldn't you have been interchanging?
couldn't he have been interchanging?
couldn't we have been interchanging?
couldn't you have been interchanging?
couldn't they have been interchanging?