could derive
Verbo regular: derive - derived- derived

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could derive
you could derive
he could derive
we could derive
you could derive
they could derive 	I could be deriving
you could be deriving
he could be deriving
we could be deriving
you could be deriving
they could be deriving	I could have derived
you could have derived
he could have derived
we could have derived
you could have derived
they could have derived	I could have been deriving
you could have been deriving
he could have been deriving
we could have been deriving
you could have been deriving
they could have been deriving	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't derive
you couldn't derive
he couldn't derive
we couldn't derive
you couldn't derive
they couldn't derive 	I couldn't be deriving
you couldn't be deriving
he couldn't be deriving
we couldn't be deriving
you couldn't be deriving
they couldn't be deriving	I couldn't have derived
you couldn't have derived
he couldn't have derived
we couldn't have derived
you couldn't have derived
they couldn't have derived	I couldn't have been deriving
you couldn't have been deriving
he couldn't have been deriving
we couldn't have been deriving
you couldn't have been deriving
they couldn't have been deriving	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I derive?
could you derive?
could he derive?
could we derive?
could you derive?
could they derive? 	could I be deriving?
could you be deriving?
could he be deriving?
could we be deriving?
could you be deriving?
could they be deriving? 	could I have derived?
could you have derived?
could he have derived?
could we have derived?
could you have derived?
could they have derived? 	could I have been deriving?
could you have been deriving?
could he have been deriving?
could we have been deriving?
could you have been deriving?
could they have been deriving? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I derive?
couldn't you derive?
couldn't he derive?
couldn't we derive?
couldn't you derive?
couldn't they derive? 	couldn't I be deriving?
couldn't you be deriving?
couldn't he be deriving?
couldn't we be deriving?
couldn't you be deriving?
couldn't they be deriving? 	couldn't I have derived?
couldn't you have derived?
couldn't he have derived?
couldn't we have derived?
couldn't you have derived?
couldn't they have derived? 	couldn't I have been deriving?
couldn't you have been deriving?
couldn't he have been deriving?
couldn't we have been deriving?
couldn't you have been deriving?
couldn't they have been deriving?