I must witness you must witness he must witness we must witness you must witness they must witness
V-ing form
I must be witnessing you must be witnessing he must be witnessing we must be witnessing you must be witnessing they must be witnessing
Perfect
I must have witnessed you must have witnessed he 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 he must have been witnessing we must have been witnessing you must have been witnessing they must have been witnessing
Negation
Simple form
I must not witness you must not witness he must not witness we must not witness you must not witness they must not witness
V-ing form
I must not be witnessing you must not be witnessing he must not be witnessing we must not be witnessing you must not be witnessing they must not be witnessing
Perfect
I must not have witnessed you must not have witnessed he must not have witnessed we must not have witnessed you must not have witnessed they must not have witnessed
V-ing perfect
I must not have been witnessing you must not have been witnessing he must not have been witnessing we must not have been witnessing you must not have been witnessing they must not have been witnessing
Interrogative form
Simple form
must I witness? must you witness? must he witness? must we witness? must you witness? must they witness?
V-ing form
must I be witnessing? must you be witnessing? must he be witnessing? must we be witnessing? must you be witnessing? must they be witnessing?
Perfect
must I have witnessed? must you have witnessed? must he 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 he have been witnessing? must we have been witnessing? must you have been witnessing? must they have been witnessing?
Interro-negative form
Simple form
must I not witness? must you not witness? must he not witness? must we not witness? must you not witness? must they not witness?
V-ing form
must I not be witnessing? must you not be witnessing? must he not be witnessing? must we not be witnessing? must you not be witnessing? must they not be witnessing?
Perfect
must I not have witnessed? must you not have witnessed? must he not have witnessed? must we not have witnessed? must you not have witnessed? must they not have witnessed?
V-ing perfect
must I not have been witnessing? must you not have been witnessing? must he not have been witnessing? must we not have been witnessing? must you not have been witnessing? must they not have been witnessing?