could crack
Verbo regular: crack - cracked- cracked

Afirmação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I could crack
you could crack
he could crack
we could crack
you could crack
they could crack 	I could be cracking
you could be cracking
he could be cracking
we could be cracking
you could be cracking
they could be cracking	I could have cracked
you could have cracked
he could have cracked
we could have cracked
you could have cracked
they could have cracked	I could have been cracking
you could have been cracking
he could have been cracking
we could have been cracking
you could have been cracking
they could have been cracking	

Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
I couldn't crack
you couldn't crack
he couldn't crack
we couldn't crack
you couldn't crack
they couldn't crack 	I couldn't be cracking
you couldn't be cracking
he couldn't be cracking
we couldn't be cracking
you couldn't be cracking
they couldn't be cracking	I couldn't have cracked
you couldn't have cracked
he couldn't have cracked
we couldn't have cracked
you couldn't have cracked
they couldn't have cracked	I couldn't have been cracking
you couldn't have been cracking
he couldn't have been cracking
we couldn't have been cracking
you couldn't have been cracking
they couldn't have been cracking	

Forma interrogativa 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
could I crack?
could you crack?
could he crack?
could we crack?
could you crack?
could they crack? 	could I be cracking?
could you be cracking?
could he be cracking?
could we be cracking?
could you be cracking?
could they be cracking? 	could I have cracked?
could you have cracked?
could he have cracked?
could we have cracked?
could you have cracked?
could they have cracked? 	could I have been cracking?
could you have been cracking?
could he have been cracking?
could we have been cracking?
could you have been cracking?
could they have been cracking? 	

Forma interro-Negação 	
Forma simple 	Forma com V-ing 	Perfeito 	Perfeito com V-ing 	
couldn't I crack?
couldn't you crack?
couldn't he crack?
couldn't we crack?
couldn't you crack?
couldn't they crack? 	couldn't I be cracking?
couldn't you be cracking?
couldn't he be cracking?
couldn't we be cracking?
couldn't you be cracking?
couldn't they be cracking? 	couldn't I have cracked?
couldn't you have cracked?
couldn't he have cracked?
couldn't we have cracked?
couldn't you have cracked?
couldn't they have cracked? 	couldn't I have been cracking?
couldn't you have been cracking?
couldn't he have been cracking?
couldn't we have been cracking?
couldn't you have been cracking?
couldn't they have been cracking?