I could preascertain you could preascertain he could preascertain we could preascertain you could preascertain they could preascertain
Forme en V-ing
I could be preascertaining you could be preascertaining he could be preascertaining we could be preascertaining you could be preascertaining they could be preascertaining
Perfect
I could have preascertained you could have preascertained he could have preascertained we could have preascertained you could have preascertained they could have preascertained
Perfect en V-ing
I could have been preascertaining you could have been preascertaining he could have been preascertaining we could have been preascertaining you could have been preascertaining they could have been preascertaining
Négation
Forme simple
I could not preascertain you could not preascertain he could not preascertain we could not preascertain you could not preascertain they could not preascertain
Forme en V-ing
I could not be preascertaining you could not be preascertaining he could not be preascertaining we could not be preascertaining you could not be preascertaining they could not be preascertaining
Perfect
I could not have preascertained you could not have preascertained he could not have preascertained we could not have preascertained you could not have preascertained they could not have preascertained
Perfect en V-ing
I could not have been preascertaining you could not have been preascertaining he could not have been preascertaining we could not have been preascertaining you could not have been preascertaining they could not have been preascertaining
Forme interrogative
Forme simple
could I preascertain? could you preascertain? could he preascertain? could we preascertain? could you preascertain? could they preascertain?
Forme en V-ing
could I be preascertaining? could you be preascertaining? could he be preascertaining? could we be preascertaining? could you be preascertaining? could they be preascertaining?
Perfect
could I have preascertained? could you have preascertained? could he have preascertained? could we have preascertained? could you have preascertained? could they have preascertained?
Perfect en V-ing
could I have been preascertaining? could you have been preascertaining? could he have been preascertaining? could we have been preascertaining? could you have been preascertaining? could they have been preascertaining?
Forme interro-négative
Forme simple
could I not preascertain? could you not preascertain? could he not preascertain? could we not preascertain? could you not preascertain? could they not preascertain?
Forme en V-ing
could I not be preascertaining? could you not be preascertaining? could he not be preascertaining? could we not be preascertaining? could you not be preascertaining? could they not be preascertaining?
Perfect
could I not have preascertained? could you not have preascertained? could he not have preascertained? could we not have preascertained? could you not have preascertained? could they not have preascertained?
Perfect en V-ing
could I not have been preascertaining? could you not have been preascertaining? could he not have been preascertaining? could we not have been preascertaining? could you not have been preascertaining? could they not have been preascertaining?