could vibrate
Verbo regular: vibrate - vibrated- vibrated

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could vibrate
you could vibrate
he could vibrate
we could vibrate
you could vibrate
they could vibrate 	I could be vibrating
you could be vibrating
he could be vibrating
we could be vibrating
you could be vibrating
they could be vibrating	I could have vibrated
you could have vibrated
he could have vibrated
we could have vibrated
you could have vibrated
they could have vibrated	I could have been vibrating
you could have been vibrating
he could have been vibrating
we could have been vibrating
you could have been vibrating
they could have been vibrating	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't vibrate
you couldn't vibrate
he couldn't vibrate
we couldn't vibrate
you couldn't vibrate
they couldn't vibrate 	I couldn't be vibrating
you couldn't be vibrating
he couldn't be vibrating
we couldn't be vibrating
you couldn't be vibrating
they couldn't be vibrating	I couldn't have vibrated
you couldn't have vibrated
he couldn't have vibrated
we couldn't have vibrated
you couldn't have vibrated
they couldn't have vibrated	I couldn't have been vibrating
you couldn't have been vibrating
he couldn't have been vibrating
we couldn't have been vibrating
you couldn't have been vibrating
they couldn't have been vibrating	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I vibrate?
could you vibrate?
could he vibrate?
could we vibrate?
could you vibrate?
could they vibrate? 	could I be vibrating?
could you be vibrating?
could he be vibrating?
could we be vibrating?
could you be vibrating?
could they be vibrating? 	could I have vibrated?
could you have vibrated?
could he have vibrated?
could we have vibrated?
could you have vibrated?
could they have vibrated? 	could I have been vibrating?
could you have been vibrating?
could he have been vibrating?
could we have been vibrating?
could you have been vibrating?
could they have been vibrating? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I vibrate?
couldn't you vibrate?
couldn't he vibrate?
couldn't we vibrate?
couldn't you vibrate?
couldn't they vibrate? 	couldn't I be vibrating?
couldn't you be vibrating?
couldn't he be vibrating?
couldn't we be vibrating?
couldn't you be vibrating?
couldn't they be vibrating? 	couldn't I have vibrated?
couldn't you have vibrated?
couldn't he have vibrated?
couldn't we have vibrated?
couldn't you have vibrated?
couldn't they have vibrated? 	couldn't I have been vibrating?
couldn't you have been vibrating?
couldn't he have been vibrating?
couldn't we have been vibrating?
couldn't you have been vibrating?
couldn't they have been vibrating?