must tinker
Regular verb: tinker - tinkered- tinkered

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must tinker
you must tinker
he must tinker
we must tinker
you must tinker
they must tinker 	I must be tinkering
you must be tinkering
he must be tinkering
we must be tinkering
you must be tinkering
they must be tinkering	I must have tinkered
you must have tinkered
he must have tinkered
we must have tinkered
you must have tinkered
they must have tinkered	I must have been tinkering
you must have been tinkering
he must have been tinkering
we must have been tinkering
you must have been tinkering
they must have been tinkering	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't tinker
you mustn't tinker
he mustn't tinker
we mustn't tinker
you mustn't tinker
they mustn't tinker 	I mustn't be tinkering
you mustn't be tinkering
he mustn't be tinkering
we mustn't be tinkering
you mustn't be tinkering
they mustn't be tinkering	I mustn't have tinkered
you mustn't have tinkered
he mustn't have tinkered
we mustn't have tinkered
you mustn't have tinkered
they mustn't have tinkered	I mustn't have been tinkering
you mustn't have been tinkering
he mustn't have been tinkering
we mustn't have been tinkering
you mustn't have been tinkering
they mustn't have been tinkering	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I tinker?
must you tinker?
must he tinker?
must we tinker?
must you tinker?
must they tinker? 	must I be tinkering?
must you be tinkering?
must he be tinkering?
must we be tinkering?
must you be tinkering?
must they be tinkering? 	must I have tinkered?
must you have tinkered?
must he have tinkered?
must we have tinkered?
must you have tinkered?
must they have tinkered? 	must I have been tinkering?
must you have been tinkering?
must he have been tinkering?
must we have been tinkering?
must you have been tinkering?
must they have been tinkering? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I tinker?
mustn't you tinker?
mustn't he tinker?
mustn't we tinker?
mustn't you tinker?
mustn't they tinker? 	mustn't I be tinkering?
mustn't you be tinkering?
mustn't he be tinkering?
mustn't we be tinkering?
mustn't you be tinkering?
mustn't they be tinkering? 	mustn't I have tinkered?
mustn't you have tinkered?
mustn't he have tinkered?
mustn't we have tinkered?
mustn't you have tinkered?
mustn't they have tinkered? 	mustn't I have been tinkering?
mustn't you have been tinkering?
mustn't he have been tinkering?
mustn't we have been tinkering?
mustn't you have been tinkering?
mustn't they have been tinkering?