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