I can ascertain you can ascertain she can ascertain we can ascertain you can ascertain they can ascertain
Forme en V-ing
I can be ascertaining you can be ascertaining she can be ascertaining we can be ascertaining you can be ascertaining they can be ascertaining
Perfect
I can have ascertained you can have ascertained she can have ascertained we can have ascertained you can have ascertained they can have ascertained
Perfect en V-ing
I can have been ascertaining you can have been ascertaining she can have been ascertaining we can have been ascertaining you can have been ascertaining they can have been ascertaining
Négation
Forme simple
I cannot ascertain you cannot ascertain she cannot ascertain we cannot ascertain you cannot ascertain they cannot ascertain
Forme en V-ing
I cannot be ascertaining you cannot be ascertaining she cannot be ascertaining we cannot be ascertaining you cannot be ascertaining they cannot be ascertaining
Perfect
I cannot have ascertained you cannot have ascertained she cannot have ascertained we cannot have ascertained you cannot have ascertained they cannot have ascertained
Perfect en V-ing
I cannot have been ascertaining you cannot have been ascertaining she cannot have been ascertaining we cannot have been ascertaining you cannot have been ascertaining they cannot have been ascertaining
Forme interrogative
Forme simple
can I ascertain? can you ascertain? can she ascertain? can we ascertain? can you ascertain? can they ascertain?
Forme en V-ing
can I be ascertaining? can you be ascertaining? can she be ascertaining? can we be ascertaining? can you be ascertaining? can they be ascertaining?
Perfect
can I have ascertained? can you have ascertained? can she have ascertained? can we have ascertained? can you have ascertained? can they have ascertained?
Perfect en V-ing
can I have been ascertaining? can you have been ascertaining? can she have been ascertaining? can we have been ascertaining? can you have been ascertaining? can they have been ascertaining?
Forme interro-négative
Forme simple
can I not ascertain? can you not ascertain? can she not ascertain? can we not ascertain? can you not ascertain? can they not ascertain?
Forme en V-ing
can I not be ascertaining? can you not be ascertaining? can she not be ascertaining? can we not be ascertaining? can you not be ascertaining? can they not be ascertaining?
Perfect
can I not have ascertained? can you not have ascertained? can she not have ascertained? can we not have ascertained? can you not have ascertained? can they not have ascertained?
Perfect en V-ing
can I not have been ascertaining? can you not have been ascertaining? can she not have been ascertaining? can we not have been ascertaining? can you not have been ascertaining? can they not have been ascertaining?