could mast
Verbo regular: mast - masted- masted

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could mast
you could mast
he could mast
we could mast
you could mast
they could mast 	I could be masting
you could be masting
he could be masting
we could be masting
you could be masting
they could be masting	I could have masted
you could have masted
he could have masted
we could have masted
you could have masted
they could have masted	I could have been masting
you could have been masting
he could have been masting
we could have been masting
you could have been masting
they could have been masting	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't mast
you couldn't mast
he couldn't mast
we couldn't mast
you couldn't mast
they couldn't mast 	I couldn't be masting
you couldn't be masting
he couldn't be masting
we couldn't be masting
you couldn't be masting
they couldn't be masting	I couldn't have masted
you couldn't have masted
he couldn't have masted
we couldn't have masted
you couldn't have masted
they couldn't have masted	I couldn't have been masting
you couldn't have been masting
he couldn't have been masting
we couldn't have been masting
you couldn't have been masting
they couldn't have been masting	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I mast?
could you mast?
could he mast?
could we mast?
could you mast?
could they mast? 	could I be masting?
could you be masting?
could he be masting?
could we be masting?
could you be masting?
could they be masting? 	could I have masted?
could you have masted?
could he have masted?
could we have masted?
could you have masted?
could they have masted? 	could I have been masting?
could you have been masting?
could he have been masting?
could we have been masting?
could you have been masting?
could they have been masting? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I mast?
couldn't you mast?
couldn't he mast?
couldn't we mast?
couldn't you mast?
couldn't they mast? 	couldn't I be masting?
couldn't you be masting?
couldn't he be masting?
couldn't we be masting?
couldn't you be masting?
couldn't they be masting? 	couldn't I have masted?
couldn't you have masted?
couldn't he have masted?
couldn't we have masted?
couldn't you have masted?
couldn't they have masted? 	couldn't I have been masting?
couldn't you have been masting?
couldn't he have been masting?
couldn't we have been masting?
couldn't you have been masting?
couldn't they have been masting?