I must think you must think he must think we must think you must think they must think
V-ing form
I must be thinking you must be thinking he must be thinking we must be thinking you must be thinking they must be thinking
Perfect
I must have thought you must have thought he must have thought we must have thought you must have thought they must have thought
V-ing perfect
I must have been thinking you must have been thinking he must have been thinking we must have been thinking you must have been thinking they must have been thinking
Negation
Simple form
I mustn't think you mustn't think he mustn't think we mustn't think you mustn't think they mustn't think
V-ing form
I mustn't be thinking you mustn't be thinking he mustn't be thinking we mustn't be thinking you mustn't be thinking they mustn't be thinking
Perfect
I mustn't have thought you mustn't have thought he mustn't have thought we mustn't have thought you mustn't have thought they mustn't have thought
V-ing perfect
I mustn't have been thinking you mustn't have been thinking he mustn't have been thinking we mustn't have been thinking you mustn't have been thinking they mustn't have been thinking
Interrogative form
Simple form
must I think? must you think? must he think? must we think? must you think? must they think?
V-ing form
must I be thinking? must you be thinking? must he be thinking? must we be thinking? must you be thinking? must they be thinking?
Perfect
must I have thought? must you have thought? must he have thought? must we have thought? must you have thought? must they have thought?
V-ing perfect
must I have been thinking? must you have been thinking? must he have been thinking? must we have been thinking? must you have been thinking? must they have been thinking?
Interro-negative form
Simple form
mustn't I think? mustn't you think? mustn't he think? mustn't we think? mustn't you think? mustn't they think?
V-ing form
mustn't I be thinking? mustn't you be thinking? mustn't he be thinking? mustn't we be thinking? mustn't you be thinking? mustn't they be thinking?
Perfect
mustn't I have thought? mustn't you have thought? mustn't he have thought? mustn't we have thought? mustn't you have thought? mustn't they have thought?
V-ing perfect
mustn't I have been thinking? mustn't you have been thinking? mustn't he have been thinking? mustn't we have been thinking? mustn't you have been thinking? mustn't they have been thinking?