I must shift you must shift she must shift we must shift you must shift they must shift
V-ing form
I must be shifting you must be shifting she must be shifting we must be shifting you must be shifting they must be shifting
Perfect
I must have shifted you must have shifted she must have shifted we must have shifted you must have shifted they must have shifted
V-ing perfect
I must have been shifting you must have been shifting she must have been shifting we must have been shifting you must have been shifting they must have been shifting
Negation
Simple form
I mustn't shift you mustn't shift she mustn't shift we mustn't shift you mustn't shift they mustn't shift
V-ing form
I mustn't be shifting you mustn't be shifting she mustn't be shifting we mustn't be shifting you mustn't be shifting they mustn't be shifting
Perfect
I mustn't have shifted you mustn't have shifted she mustn't have shifted we mustn't have shifted you mustn't have shifted they mustn't have shifted
V-ing perfect
I mustn't have been shifting you mustn't have been shifting she mustn't have been shifting we mustn't have been shifting you mustn't have been shifting they mustn't have been shifting
Interrogative form
Simple form
must I shift? must you shift? must she shift? must we shift? must you shift? must they shift?
V-ing form
must I be shifting? must you be shifting? must she be shifting? must we be shifting? must you be shifting? must they be shifting?
Perfect
must I have shifted? must you have shifted? must she have shifted? must we have shifted? must you have shifted? must they have shifted?
V-ing perfect
must I have been shifting? must you have been shifting? must she have been shifting? must we have been shifting? must you have been shifting? must they have been shifting?
Interro-negative form
Simple form
mustn't I shift? mustn't you shift? mustn't she shift? mustn't we shift? mustn't you shift? mustn't they shift?
V-ing form
mustn't I be shifting? mustn't you be shifting? mustn't she be shifting? mustn't we be shifting? mustn't you be shifting? mustn't they be shifting?
Perfect
mustn't I have shifted? mustn't you have shifted? mustn't she have shifted? mustn't we have shifted? mustn't you have shifted? mustn't they have shifted?
V-ing perfect
mustn't I have been shifting? mustn't you have been shifting? mustn't she have been shifting? mustn't we have been shifting? mustn't you have been shifting? mustn't they have been shifting?