could thicken
Verbo regular: thicken - thickened- thickened

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could thicken
you could thicken
he could thicken
we could thicken
you could thicken
they could thicken 	I could be thickening
you could be thickening
he could be thickening
we could be thickening
you could be thickening
they could be thickening	I could have thickened
you could have thickened
he could have thickened
we could have thickened
you could have thickened
they could have thickened	I could have been thickening
you could have been thickening
he could have been thickening
we could have been thickening
you could have been thickening
they could have been thickening	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could not thicken
you could not thicken
he could not thicken
we could not thicken
you could not thicken
they could not thicken 	I could not be thickening
you could not be thickening
he could not be thickening
we could not be thickening
you could not be thickening
they could not be thickening	I could not have thickened
you could not have thickened
he could not have thickened
we could not have thickened
you could not have thickened
they could not have thickened	I could not have been thickening
you could not have been thickening
he could not have been thickening
we could not have been thickening
you could not have been thickening
they could not have been thickening	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I thicken?
could you thicken?
could he thicken?
could we thicken?
could you thicken?
could they thicken? 	could I be thickening?
could you be thickening?
could he be thickening?
could we be thickening?
could you be thickening?
could they be thickening? 	could I have thickened?
could you have thickened?
could he have thickened?
could we have thickened?
could you have thickened?
could they have thickened? 	could I have been thickening?
could you have been thickening?
could he have been thickening?
could we have been thickening?
could you have been thickening?
could they have been thickening? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I not thicken?
could you not thicken?
could he not thicken?
could we not thicken?
could you not thicken?
could they not thicken? 	could I not be thickening?
could you not be thickening?
could he not be thickening?
could we not be thickening?
could you not be thickening?
could they not be thickening? 	could I not have thickened?
could you not have thickened?
could he not have thickened?
could we not have thickened?
could you not have thickened?
could they not have thickened? 	could I not have been thickening?
could you not have been thickening?
could he not have been thickening?
could we not have been thickening?
could you not have been thickening?
could they not have been thickening?