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