English verb conjugation
MUST PIERCE

Regular verb: pierce - pierced - pierced

Affirmation

Simple form	V-ing form
I must pierce you must pierce she must pierce we must pierce you must pierce they must pierce	I must be piercing you must be piercing she must be piercing we must be piercing you must be piercing they must be piercing
Perfect	V-ing perfect
I must have pierced you must have pierced she must have pierced we must have pierced you must have pierced they must have pierced	I must have been piercing you must have been piercing she must have been piercing we must have been piercing you must have been piercing they must have been piercing

Negation

Simple form	V-ing form
I mustn't pierce you mustn't pierce she mustn't pierce we mustn't pierce you mustn't pierce they mustn't pierce	I mustn't be piercing you mustn't be piercing she mustn't be piercing we mustn't be piercing you mustn't be piercing they mustn't be piercing
Perfect	V-ing perfect
I mustn't have pierced you mustn't have pierced she mustn't have pierced we mustn't have pierced you mustn't have pierced they mustn't have pierced	I mustn't have been piercing you mustn't have been piercing she mustn't have been piercing we mustn't have been piercing you mustn't have been piercing they mustn't have been piercing

Interrogative form

Simple form	V-ing form
must I pierce? must you pierce? must she pierce? must we pierce? must you pierce? must they pierce?	must I be piercing? must you be piercing? must she be piercing? must we be piercing? must you be piercing? must they be piercing?
Perfect	V-ing perfect
must I have pierced? must you have pierced? must she have pierced? must we have pierced? must you have pierced? must they have pierced?	must I have been piercing? must you have been piercing? must she have been piercing? must we have been piercing? must you have been piercing? must they have been piercing?

Interro-negative form

Simple form	V-ing form
mustn't I pierce? mustn't you pierce? mustn't she pierce? mustn't we pierce? mustn't you pierce? mustn't they pierce?	mustn't I be piercing? mustn't you be piercing? mustn't she be piercing? mustn't we be piercing? mustn't you be piercing? mustn't they be piercing?
Perfect	V-ing perfect
mustn't I have pierced? mustn't you have pierced? mustn't she have pierced? mustn't we have pierced? mustn't you have pierced? mustn't they have pierced?	mustn't I have been piercing? mustn't you have been piercing? mustn't she have been piercing? mustn't we have been piercing? mustn't you have been piercing? mustn't they have been piercing?