Conjugación del verbo inglés
SHOULD HAPPEN

Verbo regular: happen - happened - happened

Afirmación

Forma simple	Forma con V-ing
- - it should happen - - -	- - it should be happening - - -
Perfecto	Perfecto con V-ing
- - it should have happened - - -	- - it should have been happening - - -

Negación

Forma simple	Forma con V-ing
- - it should not happen - - -	- - it should not be happening - - -
Perfecto	Perfecto con V-ing
- - it should not have happened - - -	- - it should not have been happening - - -

Forma interrogativa

Forma simple	Forma con V-ing
- - should it happen? - - -	- - should it be happening? - - -
Perfecto	Perfecto con V-ing
- - should it have happened? - - -	- - should it have been happening? - - -

Forma interro-negativa

Forma simple	Forma con V-ing
- - should it not happen? - - -	- - should it not be happening? - - -
Perfecto	Perfecto con V-ing
- - should it not have happened? - - -	- - should it not have been happening? - - -