could ascertain
Verbe régulier : ascertain - ascertained- ascertained
Traduction française : établir - constater 

Affirmation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I could ascertain
you could ascertain
she could ascertain
we could ascertain
you could ascertain
they could ascertain 	I could be ascertaining
you could be ascertaining
she could be ascertaining
we could be ascertaining
you could be ascertaining
they could be ascertaining	I could have ascertained
you could have ascertained
she could have ascertained
we could have ascertained
you could have ascertained
they could have ascertained	I could have been ascertaining
you could have been ascertaining
she could have been ascertaining
we could have been ascertaining
you could have been ascertaining
they could have been ascertaining	

Négation 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
I couldn't ascertain
you couldn't ascertain
she couldn't ascertain
we couldn't ascertain
you couldn't ascertain
they couldn't ascertain 	I couldn't be ascertaining
you couldn't be ascertaining
she couldn't be ascertaining
we couldn't be ascertaining
you couldn't be ascertaining
they couldn't be ascertaining	I couldn't have ascertained
you couldn't have ascertained
she couldn't have ascertained
we couldn't have ascertained
you couldn't have ascertained
they couldn't have ascertained	I couldn't have been ascertaining
you couldn't have been ascertaining
she couldn't have been ascertaining
we couldn't have been ascertaining
you couldn't have been ascertaining
they couldn't have been ascertaining	

Forme interrogative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
could I ascertain?
could you ascertain?
could she ascertain?
could we ascertain?
could you ascertain?
could they ascertain? 	could I be ascertaining?
could you be ascertaining?
could she be ascertaining?
could we be ascertaining?
could you be ascertaining?
could they be ascertaining? 	could I have ascertained?
could you have ascertained?
could she have ascertained?
could we have ascertained?
could you have ascertained?
could they have ascertained? 	could I have been ascertaining?
could you have been ascertaining?
could she have been ascertaining?
could we have been ascertaining?
could you have been ascertaining?
could they have been ascertaining? 	

Forme interro-négative 	
Forme simple 	Forme en V-ing 	Perfect 	Perfect en V-ing 	
couldn't I ascertain?
couldn't you ascertain?
couldn't she ascertain?
couldn't we ascertain?
couldn't you ascertain?
couldn't they ascertain? 	couldn't I be ascertaining?
couldn't you be ascertaining?
couldn't she be ascertaining?
couldn't we be ascertaining?
couldn't you be ascertaining?
couldn't they be ascertaining? 	couldn't I have ascertained?
couldn't you have ascertained?
couldn't she have ascertained?
couldn't we have ascertained?
couldn't you have ascertained?
couldn't they have ascertained? 	couldn't I have been ascertaining?
couldn't you have been ascertaining?
couldn't she have been ascertaining?
couldn't we have been ascertaining?
couldn't you have been ascertaining?
couldn't they have been ascertaining?