could frost
Verbo regular: frost - frosted- frosted

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could frost
you could frost
he could frost
we could frost
you could frost
they could frost 	I could be frosting
you could be frosting
he could be frosting
we could be frosting
you could be frosting
they could be frosting	I could have frosted
you could have frosted
he could have frosted
we could have frosted
you could have frosted
they could have frosted	I could have been frosting
you could have been frosting
he could have been frosting
we could have been frosting
you could have been frosting
they could have been frosting	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't frost
you couldn't frost
he couldn't frost
we couldn't frost
you couldn't frost
they couldn't frost 	I couldn't be frosting
you couldn't be frosting
he couldn't be frosting
we couldn't be frosting
you couldn't be frosting
they couldn't be frosting	I couldn't have frosted
you couldn't have frosted
he couldn't have frosted
we couldn't have frosted
you couldn't have frosted
they couldn't have frosted	I couldn't have been frosting
you couldn't have been frosting
he couldn't have been frosting
we couldn't have been frosting
you couldn't have been frosting
they couldn't have been frosting	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I frost?
could you frost?
could he frost?
could we frost?
could you frost?
could they frost? 	could I be frosting?
could you be frosting?
could he be frosting?
could we be frosting?
could you be frosting?
could they be frosting? 	could I have frosted?
could you have frosted?
could he have frosted?
could we have frosted?
could you have frosted?
could they have frosted? 	could I have been frosting?
could you have been frosting?
could he have been frosting?
could we have been frosting?
could you have been frosting?
could they have been frosting? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I frost?
couldn't you frost?
couldn't he frost?
couldn't we frost?
couldn't you frost?
couldn't they frost? 	couldn't I be frosting?
couldn't you be frosting?
couldn't he be frosting?
couldn't we be frosting?
couldn't you be frosting?
couldn't they be frosting? 	couldn't I have frosted?
couldn't you have frosted?
couldn't he have frosted?
couldn't we have frosted?
couldn't you have frosted?
couldn't they have frosted? 	couldn't I have been frosting?
couldn't you have been frosting?
couldn't he have been frosting?
couldn't we have been frosting?
couldn't you have been frosting?
couldn't they have been frosting?