should back
Verbo regular: back - backed- backed

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I should back
you should back
he should back
we should back
you should back
they should back 	I should be backing
you should be backing
he should be backing
we should be backing
you should be backing
they should be backing	I should have backed
you should have backed
he should have backed
we should have backed
you should have backed
they should have backed	I should have been backing
you should have been backing
he should have been backing
we should have been backing
you should have been backing
they should have been backing	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I should not back
you should not back
he should not back
we should not back
you should not back
they should not back 	I should not be backing
you should not be backing
he should not be backing
we should not be backing
you should not be backing
they should not be backing	I should not have backed
you should not have backed
he should not have backed
we should not have backed
you should not have backed
they should not have backed	I should not have been backing
you should not have been backing
he should not have been backing
we should not have been backing
you should not have been backing
they should not have been backing	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
should I back?
should you back?
should he back?
should we back?
should you back?
should they back? 	should I be backing?
should you be backing?
should he be backing?
should we be backing?
should you be backing?
should they be backing? 	should I have backed?
should you have backed?
should he have backed?
should we have backed?
should you have backed?
should they have backed? 	should I have been backing?
should you have been backing?
should he have been backing?
should we have been backing?
should you have been backing?
should they have been backing? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
should I not back?
should you not back?
should he not back?
should we not back?
should you not back?
should they not back? 	should I not be backing?
should you not be backing?
should he not be backing?
should we not be backing?
should you not be backing?
should they not be backing? 	should I not have backed?
should you not have backed?
should he not have backed?
should we not have backed?
should you not have backed?
should they not have backed? 	should I not have been backing?
should you not have been backing?
should he not have been backing?
should we not have been backing?
should you not have been backing?
should they not have been backing?