should ascertain
Regular verb: ascertain - ascertained- ascertained

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I should ascertain
you should ascertain
she should ascertain
we should ascertain
you should ascertain
they should ascertain 	I should be ascertaining
you should be ascertaining
she should be ascertaining
we should be ascertaining
you should be ascertaining
they should be ascertaining	I should have ascertained
you should have ascertained
she should have ascertained
we should have ascertained
you should have ascertained
they should have ascertained	I should have been ascertaining
you should have been ascertaining
she should have been ascertaining
we should have been ascertaining
you should have been ascertaining
they should have been ascertaining	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I should not ascertain
you should not ascertain
she should not ascertain
we should not ascertain
you should not ascertain
they should not ascertain 	I should not be ascertaining
you should not be ascertaining
she should not be ascertaining
we should not be ascertaining
you should not be ascertaining
they should not be ascertaining	I should not have ascertained
you should not have ascertained
she should not have ascertained
we should not have ascertained
you should not have ascertained
they should not have ascertained	I should not have been ascertaining
you should not have been ascertaining
she should not have been ascertaining
we should not have been ascertaining
you should not have been ascertaining
they should not have been ascertaining	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I ascertain?
should you ascertain?
should she ascertain?
should we ascertain?
should you ascertain?
should they ascertain? 	should I be ascertaining?
should you be ascertaining?
should she be ascertaining?
should we be ascertaining?
should you be ascertaining?
should they be ascertaining? 	should I have ascertained?
should you have ascertained?
should she have ascertained?
should we have ascertained?
should you have ascertained?
should they have ascertained? 	should I have been ascertaining?
should you have been ascertaining?
should she have been ascertaining?
should we have been ascertaining?
should you have been ascertaining?
should they have been ascertaining? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
should I not ascertain?
should you not ascertain?
should she not ascertain?
should we not ascertain?
should you not ascertain?
should they not ascertain? 	should I not be ascertaining?
should you not be ascertaining?
should she not be ascertaining?
should we not be ascertaining?
should you not be ascertaining?
should they not be ascertaining? 	should I not have ascertained?
should you not have ascertained?
should she not have ascertained?
should we not have ascertained?
should you not have ascertained?
should they not have ascertained? 	should I not have been ascertaining?
should you not have been ascertaining?
should she not have been ascertaining?
should we not have been ascertaining?
should you not have been ascertaining?
should they not have been ascertaining?