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