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