I must forget you must forget she must forget we must forget you must forget they must forget
V-ing form
I must be forgetting you must be forgetting she must be forgetting we must be forgetting you must be forgetting they must be forgetting
Perfect
I must have forgotten you must have forgotten she must have forgotten we must have forgotten you must have forgotten they must have forgotten
V-ing perfect
I must have been forgetting you must have been forgetting she must have been forgetting we must have been forgetting you must have been forgetting they must have been forgetting
Negation
Simple form
I must not forget you must not forget she must not forget we must not forget you must not forget they must not forget
V-ing form
I must not be forgetting you must not be forgetting she must not be forgetting we must not be forgetting you must not be forgetting they must not be forgetting
Perfect
I must not have forgotten you must not have forgotten she must not have forgotten we must not have forgotten you must not have forgotten they must not have forgotten
V-ing perfect
I must not have been forgetting you must not have been forgetting she must not have been forgetting we must not have been forgetting you must not have been forgetting they must not have been forgetting
Interrogative form
Simple form
must I forget? must you forget? must she forget? must we forget? must you forget? must they forget?
V-ing form
must I be forgetting? must you be forgetting? must she be forgetting? must we be forgetting? must you be forgetting? must they be forgetting?
Perfect
must I have forgotten? must you have forgotten? must she have forgotten? must we have forgotten? must you have forgotten? must they have forgotten?
V-ing perfect
must I have been forgetting? must you have been forgetting? must she have been forgetting? must we have been forgetting? must you have been forgetting? must they have been forgetting?
Interro-negative form
Simple form
must I not forget? must you not forget? must she not forget? must we not forget? must you not forget? must they not forget?
V-ing form
must I not be forgetting? must you not be forgetting? must she not be forgetting? must we not be forgetting? must you not be forgetting? must they not be forgetting?
Perfect
must I not have forgotten? must you not have forgotten? must she not have forgotten? must we not have forgotten? must you not have forgotten? must they not have forgotten?
V-ing perfect
must I not have been forgetting? must you not have been forgetting? must she not have been forgetting? must we not have been forgetting? must you not have been forgetting? must they not have been forgetting?