could headbutt
Verbo regular: headbutt - headbutted- headbutted

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could headbutt
you could headbutt
he could headbutt
we could headbutt
you could headbutt
they could headbutt 	I could be headbutting
you could be headbutting
he could be headbutting
we could be headbutting
you could be headbutting
they could be headbutting	I could have headbutted
you could have headbutted
he could have headbutted
we could have headbutted
you could have headbutted
they could have headbutted	I could have been headbutting
you could have been headbutting
he could have been headbutting
we could have been headbutting
you could have been headbutting
they could have been headbutting	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not headbutt
you could not headbutt
he could not headbutt
we could not headbutt
you could not headbutt
they could not headbutt 	I could not be headbutting
you could not be headbutting
he could not be headbutting
we could not be headbutting
you could not be headbutting
they could not be headbutting	I could not have headbutted
you could not have headbutted
he could not have headbutted
we could not have headbutted
you could not have headbutted
they could not have headbutted	I could not have been headbutting
you could not have been headbutting
he could not have been headbutting
we could not have been headbutting
you could not have been headbutting
they could not have been headbutting	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I headbutt?
could you headbutt?
could he headbutt?
could we headbutt?
could you headbutt?
could they headbutt? 	could I be headbutting?
could you be headbutting?
could he be headbutting?
could we be headbutting?
could you be headbutting?
could they be headbutting? 	could I have headbutted?
could you have headbutted?
could he have headbutted?
could we have headbutted?
could you have headbutted?
could they have headbutted? 	could I have been headbutting?
could you have been headbutting?
could he have been headbutting?
could we have been headbutting?
could you have been headbutting?
could they have been headbutting? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not headbutt?
could you not headbutt?
could he not headbutt?
could we not headbutt?
could you not headbutt?
could they not headbutt? 	could I not be headbutting?
could you not be headbutting?
could he not be headbutting?
could we not be headbutting?
could you not be headbutting?
could they not be headbutting? 	could I not have headbutted?
could you not have headbutted?
could he not have headbutted?
could we not have headbutted?
could you not have headbutted?
could they not have headbutted? 	could I not have been headbutting?
could you not have been headbutting?
could he not have been headbutting?
could we not have been headbutting?
could you not have been headbutting?
could they not have been headbutting?