I must trouble you must trouble he must trouble we must trouble you must trouble they must trouble
V-ing form
I must be troubling you must be troubling he must be troubling we must be troubling you must be troubling they must be troubling
Perfect
I must have troubled you must have troubled he 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 he 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 he 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 he 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 he 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 he 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 he trouble? must we trouble? must you trouble? must they trouble?
V-ing form
must I be troubling? must you be troubling? must he be troubling? must we be troubling? must you be troubling? must they be troubling?
Perfect
must I have troubled? must you have troubled? must he 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 he 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 he 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 he 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 he 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 he have been troubling? mustn't we have been troubling? mustn't you have been troubling? mustn't they have been troubling?