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