I must prick you must prick he must prick we must prick you must prick they must prick
V-ing form
I must be pricking you must be pricking he must be pricking we must be pricking you must be pricking they must be pricking
Perfect
I must have pricked you must have pricked he must have pricked we must have pricked you must have pricked they must have pricked
V-ing perfect
I must have been pricking you must have been pricking he must have been pricking we must have been pricking you must have been pricking they must have been pricking
Negation
Simple form
I mustn't prick you mustn't prick he mustn't prick we mustn't prick you mustn't prick they mustn't prick
V-ing form
I mustn't be pricking you mustn't be pricking he mustn't be pricking we mustn't be pricking you mustn't be pricking they mustn't be pricking
Perfect
I mustn't have pricked you mustn't have pricked he mustn't have pricked we mustn't have pricked you mustn't have pricked they mustn't have pricked
V-ing perfect
I mustn't have been pricking you mustn't have been pricking he mustn't have been pricking we mustn't have been pricking you mustn't have been pricking they mustn't have been pricking
Interrogative form
Simple form
must I prick? must you prick? must he prick? must we prick? must you prick? must they prick?
V-ing form
must I be pricking? must you be pricking? must he be pricking? must we be pricking? must you be pricking? must they be pricking?
Perfect
must I have pricked? must you have pricked? must he have pricked? must we have pricked? must you have pricked? must they have pricked?
V-ing perfect
must I have been pricking? must you have been pricking? must he have been pricking? must we have been pricking? must you have been pricking? must they have been pricking?
Interro-negative form
Simple form
mustn't I prick? mustn't you prick? mustn't he prick? mustn't we prick? mustn't you prick? mustn't they prick?
V-ing form
mustn't I be pricking? mustn't you be pricking? mustn't he be pricking? mustn't we be pricking? mustn't you be pricking? mustn't they be pricking?
Perfect
mustn't I have pricked? mustn't you have pricked? mustn't he have pricked? mustn't we have pricked? mustn't you have pricked? mustn't they have pricked?
V-ing perfect
mustn't I have been pricking? mustn't you have been pricking? mustn't he have been pricking? mustn't we have been pricking? mustn't you have been pricking? mustn't they have been pricking?