must unstrap
Regular verb: unstrap - unstrapped- unstrapped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must unstrap
you must unstrap
he must unstrap
we must unstrap
you must unstrap
they must unstrap 	I must be unstrapping
you must be unstrapping
he must be unstrapping
we must be unstrapping
you must be unstrapping
they must be unstrapping	I must have unstrapped
you must have unstrapped
he must have unstrapped
we must have unstrapped
you must have unstrapped
they must have unstrapped	I must have been unstrapping
you must have been unstrapping
he must have been unstrapping
we must have been unstrapping
you must have been unstrapping
they must have been unstrapping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't unstrap
you mustn't unstrap
he mustn't unstrap
we mustn't unstrap
you mustn't unstrap
they mustn't unstrap 	I mustn't be unstrapping
you mustn't be unstrapping
he mustn't be unstrapping
we mustn't be unstrapping
you mustn't be unstrapping
they mustn't be unstrapping	I mustn't have unstrapped
you mustn't have unstrapped
he mustn't have unstrapped
we mustn't have unstrapped
you mustn't have unstrapped
they mustn't have unstrapped	I mustn't have been unstrapping
you mustn't have been unstrapping
he mustn't have been unstrapping
we mustn't have been unstrapping
you mustn't have been unstrapping
they mustn't have been unstrapping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I unstrap?
must you unstrap?
must he unstrap?
must we unstrap?
must you unstrap?
must they unstrap? 	must I be unstrapping?
must you be unstrapping?
must he be unstrapping?
must we be unstrapping?
must you be unstrapping?
must they be unstrapping? 	must I have unstrapped?
must you have unstrapped?
must he have unstrapped?
must we have unstrapped?
must you have unstrapped?
must they have unstrapped? 	must I have been unstrapping?
must you have been unstrapping?
must he have been unstrapping?
must we have been unstrapping?
must you have been unstrapping?
must they have been unstrapping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I unstrap?
mustn't you unstrap?
mustn't he unstrap?
mustn't we unstrap?
mustn't you unstrap?
mustn't they unstrap? 	mustn't I be unstrapping?
mustn't you be unstrapping?
mustn't he be unstrapping?
mustn't we be unstrapping?
mustn't you be unstrapping?
mustn't they be unstrapping? 	mustn't I have unstrapped?
mustn't you have unstrapped?
mustn't he have unstrapped?
mustn't we have unstrapped?
mustn't you have unstrapped?
mustn't they have unstrapped? 	mustn't I have been unstrapping?
mustn't you have been unstrapping?
mustn't he have been unstrapping?
mustn't we have been unstrapping?
mustn't you have been unstrapping?
mustn't they have been unstrapping?