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 mustn't preascertain you mustn't preascertain she mustn't preascertain we mustn't preascertain you mustn't preascertain they mustn't preascertain	I mustn't be preascertaining you mustn't be preascertaining she mustn't be preascertaining we mustn't be preascertaining you mustn't be preascertaining they mustn't be preascertaining
Perfect	V-ing perfect
I mustn't have preascertained you mustn't have preascertained she mustn't have preascertained we mustn't have preascertained you mustn't have preascertained they mustn't have preascertained	I mustn't have been preascertaining you mustn't have been preascertaining she mustn't have been preascertaining we mustn't have been preascertaining you mustn't have been preascertaining they mustn't 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
mustn't I preascertain? mustn't you preascertain? mustn't she preascertain? mustn't we preascertain? mustn't you preascertain? mustn't they preascertain?	mustn't I be preascertaining? mustn't you be preascertaining? mustn't she be preascertaining? mustn't we be preascertaining? mustn't you be preascertaining? mustn't they be preascertaining?
Perfect	V-ing perfect
mustn't I have preascertained? mustn't you have preascertained? mustn't she have preascertained? mustn't we have preascertained? mustn't you have preascertained? mustn't they have preascertained?	mustn't I have been preascertaining? mustn't you have been preascertaining? mustn't she have been preascertaining? mustn't we have been preascertaining? mustn't you have been preascertaining? mustn't they have been preascertaining?