English verb conjugation
MUST SIRE

Regular verb: sire - sired - sired

Affirmation

Simple form	V-ing form
I must sire you must sire she must sire we must sire you must sire they must sire	I must be siring you must be siring she 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 she 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 she 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 mustn't sire you mustn't sire she mustn't sire we mustn't sire you mustn't sire they mustn't sire	I mustn't be siring you mustn't be siring she mustn't be siring we mustn't be siring you mustn't be siring they mustn't be siring
Perfect	V-ing perfect
I mustn't have sired you mustn't have sired she mustn't have sired we mustn't have sired you mustn't have sired they mustn't have sired	I mustn't have been siring you mustn't have been siring she mustn't have been siring we mustn't have been siring you mustn't have been siring they mustn't have been siring

Interrogative form

Simple form	V-ing form
must I sire? must you sire? must she sire? must we sire? must you sire? must they sire?	must I be siring? must you be siring? must she 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 she 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 she 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
mustn't I sire? mustn't you sire? mustn't she sire? mustn't we sire? mustn't you sire? mustn't they sire?	mustn't I be siring? mustn't you be siring? mustn't she be siring? mustn't we be siring? mustn't you be siring? mustn't they be siring?
Perfect	V-ing perfect
mustn't I have sired? mustn't you have sired? mustn't she have sired? mustn't we have sired? mustn't you have sired? mustn't they have sired?	mustn't I have been siring? mustn't you have been siring? mustn't she have been siring? mustn't we have been siring? mustn't you have been siring? mustn't they have been siring?