English verb conjugation
MUST PREASCERTAIN

Regular verb: preascertain - preascertained - preascertained

Affirmation

Simple form	V-ing form
I must preascertain you must preascertain she must preascertain we must preascertain you must preascertain they must preascertain	I must be preascertaining you must be preascertaining she must be preascertaining we must be preascertaining you must be preascertaining they must be preascertaining
Perfect	V-ing perfect
I must have preascertained you must have preascertained she must have preascertained we must have preascertained you must have preascertained they must have preascertained	I must have been preascertaining you must have been preascertaining she must have been preascertaining we must have been preascertaining you must have been preascertaining they must have been preascertaining

Negation

Simple form	V-ing form
I must not preascertain you must not preascertain she must not preascertain we must not preascertain you must not preascertain they must not preascertain	I must not be preascertaining you must not be preascertaining she must not be preascertaining we must not be preascertaining you must not be preascertaining they must not be preascertaining
Perfect	V-ing perfect
I must not have preascertained you must not have preascertained she must not have preascertained we must not have preascertained you must not have preascertained they must not have preascertained	I must not have been preascertaining you must not have been preascertaining she must not have been preascertaining we must not have been preascertaining you must not have been preascertaining they must not have been preascertaining

Interrogative form

Simple form	V-ing form
must I preascertain? must you preascertain? must she preascertain? must we preascertain? must you preascertain? must they preascertain?	must I be preascertaining? must you be preascertaining? must she be preascertaining? must we be preascertaining? must you be preascertaining? must they be preascertaining?
Perfect	V-ing perfect
must I have preascertained? must you have preascertained? must she have preascertained? must we have preascertained? must you have preascertained? must they have preascertained?	must I have been preascertaining? must you have been preascertaining? must she have been preascertaining? must we have been preascertaining? must you have been preascertaining? must they have been preascertaining?

Interro-negative form

Simple form	V-ing form
must I not preascertain? must you not preascertain? must she not preascertain? must we not preascertain? must you not preascertain? must they not preascertain?	must I not be preascertaining? must you not be preascertaining? must she not be preascertaining? must we not be preascertaining? must you not be preascertaining? must they not be preascertaining?
Perfect	V-ing perfect
must I not have preascertained? must you not have preascertained? must she not have preascertained? must we not have preascertained? must you not have preascertained? must they not have preascertained?	must I not have been preascertaining? must you not have been preascertaining? must she not have been preascertaining? must we not have been preascertaining? must you not have been preascertaining? must they not have been preascertaining?