could crumble
Verbo regular: crumble - crumbled- crumbled

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could crumble
you could crumble
he could crumble
we could crumble
you could crumble
they could crumble 	I could be crumbling
you could be crumbling
he could be crumbling
we could be crumbling
you could be crumbling
they could be crumbling	I could have crumbled
you could have crumbled
he could have crumbled
we could have crumbled
you could have crumbled
they could have crumbled	I could have been crumbling
you could have been crumbling
he could have been crumbling
we could have been crumbling
you could have been crumbling
they could have been crumbling	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't crumble
you couldn't crumble
he couldn't crumble
we couldn't crumble
you couldn't crumble
they couldn't crumble 	I couldn't be crumbling
you couldn't be crumbling
he couldn't be crumbling
we couldn't be crumbling
you couldn't be crumbling
they couldn't be crumbling	I couldn't have crumbled
you couldn't have crumbled
he couldn't have crumbled
we couldn't have crumbled
you couldn't have crumbled
they couldn't have crumbled	I couldn't have been crumbling
you couldn't have been crumbling
he couldn't have been crumbling
we couldn't have been crumbling
you couldn't have been crumbling
they couldn't have been crumbling	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I crumble?
could you crumble?
could he crumble?
could we crumble?
could you crumble?
could they crumble? 	could I be crumbling?
could you be crumbling?
could he be crumbling?
could we be crumbling?
could you be crumbling?
could they be crumbling? 	could I have crumbled?
could you have crumbled?
could he have crumbled?
could we have crumbled?
could you have crumbled?
could they have crumbled? 	could I have been crumbling?
could you have been crumbling?
could he have been crumbling?
could we have been crumbling?
could you have been crumbling?
could they have been crumbling? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I crumble?
couldn't you crumble?
couldn't he crumble?
couldn't we crumble?
couldn't you crumble?
couldn't they crumble? 	couldn't I be crumbling?
couldn't you be crumbling?
couldn't he be crumbling?
couldn't we be crumbling?
couldn't you be crumbling?
couldn't they be crumbling? 	couldn't I have crumbled?
couldn't you have crumbled?
couldn't he have crumbled?
couldn't we have crumbled?
couldn't you have crumbled?
couldn't they have crumbled? 	couldn't I have been crumbling?
couldn't you have been crumbling?
couldn't he have been crumbling?
couldn't we have been crumbling?
couldn't you have been crumbling?
couldn't they have been crumbling?