must shorten
Regular verb: shorten - shortened- shortened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must shorten
you must shorten
she must shorten
we must shorten
you must shorten
they must shorten 	I must be shortening
you must be shortening
she must be shortening
we must be shortening
you must be shortening
they must be shortening	I must have shortened
you must have shortened
she must have shortened
we must have shortened
you must have shortened
they must have shortened	I must have been shortening
you must have been shortening
she must have been shortening
we must have been shortening
you must have been shortening
they must have been shortening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't shorten
you mustn't shorten
she mustn't shorten
we mustn't shorten
you mustn't shorten
they mustn't shorten 	I mustn't be shortening
you mustn't be shortening
she mustn't be shortening
we mustn't be shortening
you mustn't be shortening
they mustn't be shortening	I mustn't have shortened
you mustn't have shortened
she mustn't have shortened
we mustn't have shortened
you mustn't have shortened
they mustn't have shortened	I mustn't have been shortening
you mustn't have been shortening
she mustn't have been shortening
we mustn't have been shortening
you mustn't have been shortening
they mustn't have been shortening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I shorten?
must you shorten?
must she shorten?
must we shorten?
must you shorten?
must they shorten? 	must I be shortening?
must you be shortening?
must she be shortening?
must we be shortening?
must you be shortening?
must they be shortening? 	must I have shortened?
must you have shortened?
must she have shortened?
must we have shortened?
must you have shortened?
must they have shortened? 	must I have been shortening?
must you have been shortening?
must she have been shortening?
must we have been shortening?
must you have been shortening?
must they have been shortening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I shorten?
mustn't you shorten?
mustn't she shorten?
mustn't we shorten?
mustn't you shorten?
mustn't they shorten? 	mustn't I be shortening?
mustn't you be shortening?
mustn't she be shortening?
mustn't we be shortening?
mustn't you be shortening?
mustn't they be shortening? 	mustn't I have shortened?
mustn't you have shortened?
mustn't she have shortened?
mustn't we have shortened?
mustn't you have shortened?
mustn't they have shortened? 	mustn't I have been shortening?
mustn't you have been shortening?
mustn't she have been shortening?
mustn't we have been shortening?
mustn't you have been shortening?
mustn't they have been shortening?