I must harp you must harp she must harp we must harp you must harp they must harp
V-ing form
I must be harping you must be harping she must be harping we must be harping you must be harping they must be harping
Perfect
I must have harped you must have harped she must have harped we must have harped you must have harped they must have harped
V-ing perfect
I must have been harping you must have been harping she must have been harping we must have been harping you must have been harping they must have been harping
Negation
Simple form
I mustn't harp you mustn't harp she mustn't harp we mustn't harp you mustn't harp they mustn't harp
V-ing form
I mustn't be harping you mustn't be harping she mustn't be harping we mustn't be harping you mustn't be harping they mustn't be harping
Perfect
I mustn't have harped you mustn't have harped she mustn't have harped we mustn't have harped you mustn't have harped they mustn't have harped
V-ing perfect
I mustn't have been harping you mustn't have been harping she mustn't have been harping we mustn't have been harping you mustn't have been harping they mustn't have been harping
Interrogative form
Simple form
must I harp? must you harp? must she harp? must we harp? must you harp? must they harp?
V-ing form
must I be harping? must you be harping? must she be harping? must we be harping? must you be harping? must they be harping?
Perfect
must I have harped? must you have harped? must she have harped? must we have harped? must you have harped? must they have harped?
V-ing perfect
must I have been harping? must you have been harping? must she have been harping? must we have been harping? must you have been harping? must they have been harping?
Interro-negative form
Simple form
mustn't I harp? mustn't you harp? mustn't she harp? mustn't we harp? mustn't you harp? mustn't they harp?
V-ing form
mustn't I be harping? mustn't you be harping? mustn't she be harping? mustn't we be harping? mustn't you be harping? mustn't they be harping?
Perfect
mustn't I have harped? mustn't you have harped? mustn't she have harped? mustn't we have harped? mustn't you have harped? mustn't they have harped?
V-ing perfect
mustn't I have been harping? mustn't you have been harping? mustn't she have been harping? mustn't we have been harping? mustn't you have been harping? mustn't they have been harping?