I must pierce you must pierce she must pierce we must pierce you must pierce they must pierce
V-ing form
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
I must have pierced you must have pierced she must have pierced we must have pierced you must have pierced they must have pierced
V-ing perfect
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
I mustn't pierce you mustn't pierce she mustn't pierce we mustn't pierce you mustn't pierce they mustn't pierce
V-ing form
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
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
V-ing perfect
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
must I pierce? must you pierce? must she pierce? must we pierce? must you pierce? must they pierce?
V-ing form
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
must I have pierced? must you have pierced? must she have pierced? must we have pierced? must you have pierced? must they have pierced?
V-ing perfect
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
mustn't I pierce? mustn't you pierce? mustn't she pierce? mustn't we pierce? mustn't you pierce? mustn't they pierce?
V-ing form
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
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?
V-ing perfect
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?