could demonstrate
Verbo regular: demonstrate - demonstrated- demonstrated

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could demonstrate
you could demonstrate
she could demonstrate
we could demonstrate
you could demonstrate
they could demonstrate 	I could be demonstrating
you could be demonstrating
she could be demonstrating
we could be demonstrating
you could be demonstrating
they could be demonstrating	I could have demonstrated
you could have demonstrated
she could have demonstrated
we could have demonstrated
you could have demonstrated
they could have demonstrated	I could have been demonstrating
you could have been demonstrating
she could have been demonstrating
we could have been demonstrating
you could have been demonstrating
they could have been demonstrating	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't demonstrate
you couldn't demonstrate
she couldn't demonstrate
we couldn't demonstrate
you couldn't demonstrate
they couldn't demonstrate 	I couldn't be demonstrating
you couldn't be demonstrating
she couldn't be demonstrating
we couldn't be demonstrating
you couldn't be demonstrating
they couldn't be demonstrating	I couldn't have demonstrated
you couldn't have demonstrated
she couldn't have demonstrated
we couldn't have demonstrated
you couldn't have demonstrated
they couldn't have demonstrated	I couldn't have been demonstrating
you couldn't have been demonstrating
she couldn't have been demonstrating
we couldn't have been demonstrating
you couldn't have been demonstrating
they couldn't have been demonstrating	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I demonstrate?
could you demonstrate?
could she demonstrate?
could we demonstrate?
could you demonstrate?
could they demonstrate? 	could I be demonstrating?
could you be demonstrating?
could she be demonstrating?
could we be demonstrating?
could you be demonstrating?
could they be demonstrating? 	could I have demonstrated?
could you have demonstrated?
could she have demonstrated?
could we have demonstrated?
could you have demonstrated?
could they have demonstrated? 	could I have been demonstrating?
could you have been demonstrating?
could she have been demonstrating?
could we have been demonstrating?
could you have been demonstrating?
could they have been demonstrating? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I demonstrate?
couldn't you demonstrate?
couldn't she demonstrate?
couldn't we demonstrate?
couldn't you demonstrate?
couldn't they demonstrate? 	couldn't I be demonstrating?
couldn't you be demonstrating?
couldn't she be demonstrating?
couldn't we be demonstrating?
couldn't you be demonstrating?
couldn't they be demonstrating? 	couldn't I have demonstrated?
couldn't you have demonstrated?
couldn't she have demonstrated?
couldn't we have demonstrated?
couldn't you have demonstrated?
couldn't they have demonstrated? 	couldn't I have been demonstrating?
couldn't you have been demonstrating?
couldn't she have been demonstrating?
couldn't we have been demonstrating?
couldn't you have been demonstrating?
couldn't they have been demonstrating?