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 couldn't preascertain you couldn't preascertain he couldn't preascertain we couldn't preascertain you couldn't preascertain they couldn't preascertain
Forme en V-ing
I couldn't be preascertaining you couldn't be preascertaining he couldn't be preascertaining we couldn't be preascertaining you couldn't be preascertaining they couldn't be preascertaining
Perfect
I couldn't have preascertained you couldn't have preascertained he couldn't have preascertained we couldn't have preascertained you couldn't have preascertained they couldn't have preascertained
Perfect en V-ing
I couldn't have been preascertaining you couldn't have been preascertaining he couldn't have been preascertaining we couldn't have been preascertaining you couldn't have been preascertaining they couldn't 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
couldn't I preascertain? couldn't you preascertain? couldn't he preascertain? couldn't we preascertain? couldn't you preascertain? couldn't they preascertain?
Forme en V-ing
couldn't I be preascertaining? couldn't you be preascertaining? couldn't he be preascertaining? couldn't we be preascertaining? couldn't you be preascertaining? couldn't they be preascertaining?
Perfect
couldn't I have preascertained? couldn't you have preascertained? couldn't he have preascertained? couldn't we have preascertained? couldn't you have preascertained? couldn't they have preascertained?
Perfect en V-ing
couldn't I have been preascertaining? couldn't you have been preascertaining? couldn't he have been preascertaining? couldn't we have been preascertaining? couldn't you have been preascertaining? couldn't they have been preascertaining?