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