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
he can fail
we can fail
you can fail
they can fail 	I can be failing
you can be failing
he can be failing
we can be failing
you can be failing
they can be failing	I can have failed
you can have failed
he 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
he 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 can't fail
you can't fail
he can't fail
we can't fail
you can't fail
they can't fail 	I can't be failing
you can't be failing
he can't be failing
we can't be failing
you can't be failing
they can't be failing	I can't have failed
you can't have failed
he can't have failed
we can't have failed
you can't have failed
they can't have failed	I can't have been failing
you can't have been failing
he can't have been failing
we can't have been failing
you can't have been failing
they can't have been failing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I fail?
can you fail?
can he fail?
can we fail?
can you fail?
can they fail? 	can I be failing?
can you be failing?
can he be failing?
can we be failing?
can you be failing?
can they be failing? 	can I have failed?
can you have failed?
can he 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 he 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't I fail?
can't you fail?
can't he fail?
can't we fail?
can't you fail?
can't they fail? 	can't I be failing?
can't you be failing?
can't he be failing?
can't we be failing?
can't you be failing?
can't they be failing? 	can't I have failed?
can't you have failed?
can't he have failed?
can't we have failed?
can't you have failed?
can't they have failed? 	can't I have been failing?
can't you have been failing?
can't he have been failing?
can't we have been failing?
can't you have been failing?
can't they have been failing?