must improve
Verbo regular: improve - improved- improved

Afirmación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I must improve
you must improve
he must improve
we must improve
you must improve
they must improve 	I must be improving
you must be improving
he must be improving
we must be improving
you must be improving
they must be improving	I must have improved
you must have improved
he must have improved
we must have improved
you must have improved
they must have improved	I must have been improving
you must have been improving
he must have been improving
we must have been improving
you must have been improving
they must have been improving	

Negación 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
I mustn't improve
you mustn't improve
he mustn't improve
we mustn't improve
you mustn't improve
they mustn't improve 	I mustn't be improving
you mustn't be improving
he mustn't be improving
we mustn't be improving
you mustn't be improving
they mustn't be improving	I mustn't have improved
you mustn't have improved
he mustn't have improved
we mustn't have improved
you mustn't have improved
they mustn't have improved	I mustn't have been improving
you mustn't have been improving
he mustn't have been improving
we mustn't have been improving
you mustn't have been improving
they mustn't have been improving	

Forma interrogativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
must I improve?
must you improve?
must he improve?
must we improve?
must you improve?
must they improve? 	must I be improving?
must you be improving?
must he be improving?
must we be improving?
must you be improving?
must they be improving? 	must I have improved?
must you have improved?
must he have improved?
must we have improved?
must you have improved?
must they have improved? 	must I have been improving?
must you have been improving?
must he have been improving?
must we have been improving?
must you have been improving?
must they have been improving? 	

Forma interro-negativa 	
Forma simple 	Forma con V-ing 	Perfecto 	Perfecto con V-ing 	
mustn't I improve?
mustn't you improve?
mustn't he improve?
mustn't we improve?
mustn't you improve?
mustn't they improve? 	mustn't I be improving?
mustn't you be improving?
mustn't he be improving?
mustn't we be improving?
mustn't you be improving?
mustn't they be improving? 	mustn't I have improved?
mustn't you have improved?
mustn't he have improved?
mustn't we have improved?
mustn't you have improved?
mustn't they have improved? 	mustn't I have been improving?
mustn't you have been improving?
mustn't he have been improving?
mustn't we have been improving?
mustn't you have been improving?
mustn't they have been improving?