English verb conjugation
MUST COUNTERSIGN

Regular verb: countersign - countersigned - countersigned

Affirmation

Simple form	V-ing form
I must countersign you must countersign he must countersign we must countersign you must countersign they must countersign	I must be countersigning you must be countersigning he must be countersigning we must be countersigning you must be countersigning they must be countersigning
Perfect	V-ing perfect
I must have countersigned you must have countersigned he must have countersigned we must have countersigned you must have countersigned they must have countersigned	I must have been countersigning you must have been countersigning he must have been countersigning we must have been countersigning you must have been countersigning they must have been countersigning

Negation

Simple form	V-ing form
I must not countersign you must not countersign he must not countersign we must not countersign you must not countersign they must not countersign	I must not be countersigning you must not be countersigning he must not be countersigning we must not be countersigning you must not be countersigning they must not be countersigning
Perfect	V-ing perfect
I must not have countersigned you must not have countersigned he must not have countersigned we must not have countersigned you must not have countersigned they must not have countersigned	I must not have been countersigning you must not have been countersigning he must not have been countersigning we must not have been countersigning you must not have been countersigning they must not have been countersigning

Interrogative form

Simple form	V-ing form
must I countersign? must you countersign? must he countersign? must we countersign? must you countersign? must they countersign?	must I be countersigning? must you be countersigning? must he be countersigning? must we be countersigning? must you be countersigning? must they be countersigning?
Perfect	V-ing perfect
must I have countersigned? must you have countersigned? must he have countersigned? must we have countersigned? must you have countersigned? must they have countersigned?	must I have been countersigning? must you have been countersigning? must he have been countersigning? must we have been countersigning? must you have been countersigning? must they have been countersigning?

Interro-negative form

Simple form	V-ing form
must I not countersign? must you not countersign? must he not countersign? must we not countersign? must you not countersign? must they not countersign?	must I not be countersigning? must you not be countersigning? must he not be countersigning? must we not be countersigning? must you not be countersigning? must they not be countersigning?
Perfect	V-ing perfect
must I not have countersigned? must you not have countersigned? must he not have countersigned? must we not have countersigned? must you not have countersigned? must they not have countersigned?	must I not have been countersigning? must you not have been countersigning? must he not have been countersigning? must we not have been countersigning? must you not have been countersigning? must they not have been countersigning?