could tremble
Verbo regular: tremble - trembled- trembled

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could tremble
you could tremble
he could tremble
we could tremble
you could tremble
they could tremble 	I could be trembling
you could be trembling
he could be trembling
we could be trembling
you could be trembling
they could be trembling	I could have trembled
you could have trembled
he could have trembled
we could have trembled
you could have trembled
they could have trembled	I could have been trembling
you could have been trembling
he could have been trembling
we could have been trembling
you could have been trembling
they could have been trembling	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't tremble
you couldn't tremble
he couldn't tremble
we couldn't tremble
you couldn't tremble
they couldn't tremble 	I couldn't be trembling
you couldn't be trembling
he couldn't be trembling
we couldn't be trembling
you couldn't be trembling
they couldn't be trembling	I couldn't have trembled
you couldn't have trembled
he couldn't have trembled
we couldn't have trembled
you couldn't have trembled
they couldn't have trembled	I couldn't have been trembling
you couldn't have been trembling
he couldn't have been trembling
we couldn't have been trembling
you couldn't have been trembling
they couldn't have been trembling	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I tremble?
could you tremble?
could he tremble?
could we tremble?
could you tremble?
could they tremble? 	could I be trembling?
could you be trembling?
could he be trembling?
could we be trembling?
could you be trembling?
could they be trembling? 	could I have trembled?
could you have trembled?
could he have trembled?
could we have trembled?
could you have trembled?
could they have trembled? 	could I have been trembling?
could you have been trembling?
could he have been trembling?
could we have been trembling?
could you have been trembling?
could they have been trembling? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I tremble?
couldn't you tremble?
couldn't he tremble?
couldn't we tremble?
couldn't you tremble?
couldn't they tremble? 	couldn't I be trembling?
couldn't you be trembling?
couldn't he be trembling?
couldn't we be trembling?
couldn't you be trembling?
couldn't they be trembling? 	couldn't I have trembled?
couldn't you have trembled?
couldn't he have trembled?
couldn't we have trembled?
couldn't you have trembled?
couldn't they have trembled? 	couldn't I have been trembling?
couldn't you have been trembling?
couldn't he have been trembling?
couldn't we have been trembling?
couldn't you have been trembling?
couldn't they have been trembling?