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