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