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