can fail
Verbo regular: fail - failed- failed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I can fail
you can fail
she can fail
we can fail
you can fail
they can fail 	I can be failing
you can be failing
she can be failing
we can be failing
you can be failing
they can be failing	I can have failed
you can have failed
she can have failed
we can have failed
you can have failed
they can have failed	I can have been failing
you can have been failing
she can have been failing
we can have been failing
you can have been failing
they can have been failing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I cannot fail
you cannot fail
she cannot fail
we cannot fail
you cannot fail
they cannot fail 	I cannot be failing
you cannot be failing
she cannot be failing
we cannot be failing
you cannot be failing
they cannot be failing	I cannot have failed
you cannot have failed
she cannot have failed
we cannot have failed
you cannot have failed
they cannot have failed	I cannot have been failing
you cannot have been failing
she cannot have been failing
we cannot have been failing
you cannot have been failing
they cannot have been failing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I fail?
can you fail?
can she fail?
can we fail?
can you fail?
can they fail? 	can I be failing?
can you be failing?
can she be failing?
can we be failing?
can you be failing?
can they be failing? 	can I have failed?
can you have failed?
can she have failed?
can we have failed?
can you have failed?
can they have failed? 	can I have been failing?
can you have been failing?
can she have been failing?
can we have been failing?
can you have been failing?
can they have been failing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I not fail?
can you not fail?
can she not fail?
can we not fail?
can you not fail?
can they not fail? 	can I not be failing?
can you not be failing?
can she not be failing?
can we not be failing?
can you not be failing?
can they not be failing? 	can I not have failed?
can you not have failed?
can she not have failed?
can we not have failed?
can you not have failed?
can they not have failed? 	can I not have been failing?
can you not have been failing?
can she not have been failing?
can we not have been failing?
can you not have been failing?
can they not have been failing?