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