I must burr you must burr she must burr we must burr you must burr they must burr
Forma con V-ing
I must be burring you must be burring she must be burring we must be burring you must be burring they must be burring
Perfecto
I must have burred you must have burred she must have burred we must have burred you must have burred they must have burred
Perfecto con V-ing
I must have been burring you must have been burring she must have been burring we must have been burring you must have been burring they must have been burring
Negación
Forma simple
I mustn't burr you mustn't burr she mustn't burr we mustn't burr you mustn't burr they mustn't burr
Forma con V-ing
I mustn't be burring you mustn't be burring she mustn't be burring we mustn't be burring you mustn't be burring they mustn't be burring
Perfecto
I mustn't have burred you mustn't have burred she mustn't have burred we mustn't have burred you mustn't have burred they mustn't have burred
Perfecto con V-ing
I mustn't have been burring you mustn't have been burring she mustn't have been burring we mustn't have been burring you mustn't have been burring they mustn't have been burring
Forma interrogativa
Forma simple
must I burr? must you burr? must she burr? must we burr? must you burr? must they burr?
Forma con V-ing
must I be burring? must you be burring? must she be burring? must we be burring? must you be burring? must they be burring?
Perfecto
must I have burred? must you have burred? must she have burred? must we have burred? must you have burred? must they have burred?
Perfecto con V-ing
must I have been burring? must you have been burring? must she have been burring? must we have been burring? must you have been burring? must they have been burring?
Forma interro-negativa
Forma simple
mustn't I burr? mustn't you burr? mustn't she burr? mustn't we burr? mustn't you burr? mustn't they burr?
Forma con V-ing
mustn't I be burring? mustn't you be burring? mustn't she be burring? mustn't we be burring? mustn't you be burring? mustn't they be burring?
Perfecto
mustn't I have burred? mustn't you have burred? mustn't she have burred? mustn't we have burred? mustn't you have burred? mustn't they have burred?
Perfecto con V-ing
mustn't I have been burring? mustn't you have been burring? mustn't she have been burring? mustn't we have been burring? mustn't you have been burring? mustn't they have been burring?