English verb conjugation
MUST SIRE

Regular verb: sire - sired - sired

Affirmation

Simple form	V-ing form
I must sire you must sire he must sire we must sire you must sire they must sire	I must be siring you must be siring he must be siring we must be siring you must be siring they must be siring
Perfect	V-ing perfect
I must have sired you must have sired he must have sired we must have sired you must have sired they must have sired	I must have been siring you must have been siring he must have been siring we must have been siring you must have been siring they must have been siring

Negation

Simple form	V-ing form
I must not sire you must not sire he must not sire we must not sire you must not sire they must not sire	I must not be siring you must not be siring he must not be siring we must not be siring you must not be siring they must not be siring
Perfect	V-ing perfect
I must not have sired you must not have sired he must not have sired we must not have sired you must not have sired they must not have sired	I must not have been siring you must not have been siring he must not have been siring we must not have been siring you must not have been siring they must not have been siring

Interrogative form

Simple form	V-ing form
must I sire? must you sire? must he sire? must we sire? must you sire? must they sire?	must I be siring? must you be siring? must he be siring? must we be siring? must you be siring? must they be siring?
Perfect	V-ing perfect
must I have sired? must you have sired? must he have sired? must we have sired? must you have sired? must they have sired?	must I have been siring? must you have been siring? must he have been siring? must we have been siring? must you have been siring? must they have been siring?

Interro-negative form

Simple form	V-ing form
must I not sire? must you not sire? must he not sire? must we not sire? must you not sire? must they not sire?	must I not be siring? must you not be siring? must he not be siring? must we not be siring? must you not be siring? must they not be siring?
Perfect	V-ing perfect
must I not have sired? must you not have sired? must he not have sired? must we not have sired? must you not have sired? must they not have sired?	must I not have been siring? must you not have been siring? must he not have been siring? must we not have been siring? must you not have been siring? must they not have been siring?