could practice
Verbo regular: practice - practiced- practiced

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could practice
you could practice
he could practice
we could practice
you could practice
they could practice 	I could be practicing
you could be practicing
he could be practicing
we could be practicing
you could be practicing
they could be practicing	I could have practiced
you could have practiced
he could have practiced
we could have practiced
you could have practiced
they could have practiced	I could have been practicing
you could have been practicing
he could have been practicing
we could have been practicing
you could have been practicing
they could have been practicing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't practice
you couldn't practice
he couldn't practice
we couldn't practice
you couldn't practice
they couldn't practice 	I couldn't be practicing
you couldn't be practicing
he couldn't be practicing
we couldn't be practicing
you couldn't be practicing
they couldn't be practicing	I couldn't have practiced
you couldn't have practiced
he couldn't have practiced
we couldn't have practiced
you couldn't have practiced
they couldn't have practiced	I couldn't have been practicing
you couldn't have been practicing
he couldn't have been practicing
we couldn't have been practicing
you couldn't have been practicing
they couldn't have been practicing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I practice?
could you practice?
could he practice?
could we practice?
could you practice?
could they practice? 	could I be practicing?
could you be practicing?
could he be practicing?
could we be practicing?
could you be practicing?
could they be practicing? 	could I have practiced?
could you have practiced?
could he have practiced?
could we have practiced?
could you have practiced?
could they have practiced? 	could I have been practicing?
could you have been practicing?
could he have been practicing?
could we have been practicing?
could you have been practicing?
could they have been practicing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I practice?
couldn't you practice?
couldn't he practice?
couldn't we practice?
couldn't you practice?
couldn't they practice? 	couldn't I be practicing?
couldn't you be practicing?
couldn't he be practicing?
couldn't we be practicing?
couldn't you be practicing?
couldn't they be practicing? 	couldn't I have practiced?
couldn't you have practiced?
couldn't he have practiced?
couldn't we have practiced?
couldn't you have practiced?
couldn't they have practiced? 	couldn't I have been practicing?
couldn't you have been practicing?
couldn't he have been practicing?
couldn't we have been practicing?
couldn't you have been practicing?
couldn't they have been practicing?