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