I must butterfly you must butterfly she must butterfly we must butterfly you must butterfly they must butterfly
V-ing form
I must be butterflying you must be butterflying she must be butterflying we must be butterflying you must be butterflying they must be butterflying
Perfect
I must have butterflied you must have butterflied she 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 she 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 she 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 she 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 she 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 she 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 she butterfly? must we butterfly? must you butterfly? must they butterfly?
V-ing form
must I be butterflying? must you be butterflying? must she be butterflying? must we be butterflying? must you be butterflying? must they be butterflying?
Perfect
must I have butterflied? must you have butterflied? must she 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 she 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 she 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 she 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 she 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 she have been butterflying? mustn't we have been butterflying? mustn't you have been butterflying? mustn't they have been butterflying?