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