can stiff
Verbo regular: stiff - stiffed- stiffed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I can stiff
you can stiff
he can stiff
we can stiff
you can stiff
they can stiff 	I can be stiffing
you can be stiffing
he can be stiffing
we can be stiffing
you can be stiffing
they can be stiffing	I can have stiffed
you can have stiffed
he can have stiffed
we can have stiffed
you can have stiffed
they can have stiffed	I can have been stiffing
you can have been stiffing
he can have been stiffing
we can have been stiffing
you can have been stiffing
they can have been stiffing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I cannot stiff
you cannot stiff
he cannot stiff
we cannot stiff
you cannot stiff
they cannot stiff 	I cannot be stiffing
you cannot be stiffing
he cannot be stiffing
we cannot be stiffing
you cannot be stiffing
they cannot be stiffing	I cannot have stiffed
you cannot have stiffed
he cannot have stiffed
we cannot have stiffed
you cannot have stiffed
they cannot have stiffed	I cannot have been stiffing
you cannot have been stiffing
he cannot have been stiffing
we cannot have been stiffing
you cannot have been stiffing
they cannot have been stiffing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I stiff?
can you stiff?
can he stiff?
can we stiff?
can you stiff?
can they stiff? 	can I be stiffing?
can you be stiffing?
can he be stiffing?
can we be stiffing?
can you be stiffing?
can they be stiffing? 	can I have stiffed?
can you have stiffed?
can he have stiffed?
can we have stiffed?
can you have stiffed?
can they have stiffed? 	can I have been stiffing?
can you have been stiffing?
can he have been stiffing?
can we have been stiffing?
can you have been stiffing?
can they have been stiffing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
can I not stiff?
can you not stiff?
can he not stiff?
can we not stiff?
can you not stiff?
can they not stiff? 	can I not be stiffing?
can you not be stiffing?
can he not be stiffing?
can we not be stiffing?
can you not be stiffing?
can they not be stiffing? 	can I not have stiffed?
can you not have stiffed?
can he not have stiffed?
can we not have stiffed?
can you not have stiffed?
can they not have stiffed? 	can I not have been stiffing?
can you not have been stiffing?
can he not have been stiffing?
can we not have been stiffing?
can you not have been stiffing?
can they not have been stiffing?