could zero
Verbo regular: zero - zeroed- zeroed

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could zero
you could zero
she could zero
we could zero
you could zero
they could zero 	I could be zeroing
you could be zeroing
she could be zeroing
we could be zeroing
you could be zeroing
they could be zeroing	I could have zeroed
you could have zeroed
she could have zeroed
we could have zeroed
you could have zeroed
they could have zeroed	I could have been zeroing
you could have been zeroing
she could have been zeroing
we could have been zeroing
you could have been zeroing
they could have been zeroing	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't zero
you couldn't zero
she couldn't zero
we couldn't zero
you couldn't zero
they couldn't zero 	I couldn't be zeroing
you couldn't be zeroing
she couldn't be zeroing
we couldn't be zeroing
you couldn't be zeroing
they couldn't be zeroing	I couldn't have zeroed
you couldn't have zeroed
she couldn't have zeroed
we couldn't have zeroed
you couldn't have zeroed
they couldn't have zeroed	I couldn't have been zeroing
you couldn't have been zeroing
she couldn't have been zeroing
we couldn't have been zeroing
you couldn't have been zeroing
they couldn't have been zeroing	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I zero?
could you zero?
could she zero?
could we zero?
could you zero?
could they zero? 	could I be zeroing?
could you be zeroing?
could she be zeroing?
could we be zeroing?
could you be zeroing?
could they be zeroing? 	could I have zeroed?
could you have zeroed?
could she have zeroed?
could we have zeroed?
could you have zeroed?
could they have zeroed? 	could I have been zeroing?
could you have been zeroing?
could she have been zeroing?
could we have been zeroing?
could you have been zeroing?
could they have been zeroing? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I zero?
couldn't you zero?
couldn't she zero?
couldn't we zero?
couldn't you zero?
couldn't they zero? 	couldn't I be zeroing?
couldn't you be zeroing?
couldn't she be zeroing?
couldn't we be zeroing?
couldn't you be zeroing?
couldn't they be zeroing? 	couldn't I have zeroed?
couldn't you have zeroed?
couldn't she have zeroed?
couldn't we have zeroed?
couldn't you have zeroed?
couldn't they have zeroed? 	couldn't I have been zeroing?
couldn't you have been zeroing?
couldn't she have been zeroing?
couldn't we have been zeroing?
couldn't you have been zeroing?
couldn't they have been zeroing?