could solve
Verbo regular: solve - solved- solved

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I could solve
you could solve
she could solve
we could solve
you could solve
they could solve 	I could be solving
you could be solving
she could be solving
we could be solving
you could be solving
they could be solving	I could have solved
you could have solved
she could have solved
we could have solved
you could have solved
they could have solved	I could have been solving
you could have been solving
she could have been solving
we could have been solving
you could have been solving
they could have been solving	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I couldn't solve
you couldn't solve
she couldn't solve
we couldn't solve
you couldn't solve
they couldn't solve 	I couldn't be solving
you couldn't be solving
she couldn't be solving
we couldn't be solving
you couldn't be solving
they couldn't be solving	I couldn't have solved
you couldn't have solved
she couldn't have solved
we couldn't have solved
you couldn't have solved
they couldn't have solved	I couldn't have been solving
you couldn't have been solving
she couldn't have been solving
we couldn't have been solving
you couldn't have been solving
they couldn't have been solving	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
could I solve?
could you solve?
could she solve?
could we solve?
could you solve?
could they solve? 	could I be solving?
could you be solving?
could she be solving?
could we be solving?
could you be solving?
could they be solving? 	could I have solved?
could you have solved?
could she have solved?
could we have solved?
could you have solved?
could they have solved? 	could I have been solving?
could you have been solving?
could she have been solving?
could we have been solving?
could you have been solving?
could they have been solving? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
couldn't I solve?
couldn't you solve?
couldn't she solve?
couldn't we solve?
couldn't you solve?
couldn't they solve? 	couldn't I be solving?
couldn't you be solving?
couldn't she be solving?
couldn't we be solving?
couldn't you be solving?
couldn't they be solving? 	couldn't I have solved?
couldn't you have solved?
couldn't she have solved?
couldn't we have solved?
couldn't you have solved?
couldn't they have solved? 	couldn't I have been solving?
couldn't you have been solving?
couldn't she have been solving?
couldn't we have been solving?
couldn't you have been solving?
couldn't they have been solving?