must string
Irregular verb: string - strung- strung

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must string
you must string
she must string
we must string
you must string
they must string 	I must be stringing
you must be stringing
she must be stringing
we must be stringing
you must be stringing
they must be stringing	I must have strung
you must have strung
she must have strung
we must have strung
you must have strung
they must have strung	I must have been stringing
you must have been stringing
she must have been stringing
we must have been stringing
you must have been stringing
they must have been stringing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't string
you mustn't string
she mustn't string
we mustn't string
you mustn't string
they mustn't string 	I mustn't be stringing
you mustn't be stringing
she mustn't be stringing
we mustn't be stringing
you mustn't be stringing
they mustn't be stringing	I mustn't have strung
you mustn't have strung
she mustn't have strung
we mustn't have strung
you mustn't have strung
they mustn't have strung	I mustn't have been stringing
you mustn't have been stringing
she mustn't have been stringing
we mustn't have been stringing
you mustn't have been stringing
they mustn't have been stringing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I string?
must you string?
must she string?
must we string?
must you string?
must they string? 	must I be stringing?
must you be stringing?
must she be stringing?
must we be stringing?
must you be stringing?
must they be stringing? 	must I have strung?
must you have strung?
must she have strung?
must we have strung?
must you have strung?
must they have strung? 	must I have been stringing?
must you have been stringing?
must she have been stringing?
must we have been stringing?
must you have been stringing?
must they have been stringing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I string?
mustn't you string?
mustn't she string?
mustn't we string?
mustn't you string?
mustn't they string? 	mustn't I be stringing?
mustn't you be stringing?
mustn't she be stringing?
mustn't we be stringing?
mustn't you be stringing?
mustn't they be stringing? 	mustn't I have strung?
mustn't you have strung?
mustn't she have strung?
mustn't we have strung?
mustn't you have strung?
mustn't they have strung? 	mustn't I have been stringing?
mustn't you have been stringing?
mustn't she have been stringing?
mustn't we have been stringing?
mustn't you have been stringing?
mustn't they have been stringing?