I must function you must function she must function we must function you must function they must function
V-ing form
I must be functioning you must be functioning she must be functioning we must be functioning you must be functioning they must be functioning
Perfect
I must have functioned you must have functioned she must have functioned we must have functioned you must have functioned they must have functioned
V-ing perfect
I must have been functioning you must have been functioning she must have been functioning we must have been functioning you must have been functioning they must have been functioning
Negation
Simple form
I must not function you must not function she must not function we must not function you must not function they must not function
V-ing form
I must not be functioning you must not be functioning she must not be functioning we must not be functioning you must not be functioning they must not be functioning
Perfect
I must not have functioned you must not have functioned she must not have functioned we must not have functioned you must not have functioned they must not have functioned
V-ing perfect
I must not have been functioning you must not have been functioning she must not have been functioning we must not have been functioning you must not have been functioning they must not have been functioning
Interrogative form
Simple form
must I function? must you function? must she function? must we function? must you function? must they function?
V-ing form
must I be functioning? must you be functioning? must she be functioning? must we be functioning? must you be functioning? must they be functioning?
Perfect
must I have functioned? must you have functioned? must she have functioned? must we have functioned? must you have functioned? must they have functioned?
V-ing perfect
must I have been functioning? must you have been functioning? must she have been functioning? must we have been functioning? must you have been functioning? must they have been functioning?
Interro-negative form
Simple form
must I not function? must you not function? must she not function? must we not function? must you not function? must they not function?
V-ing form
must I not be functioning? must you not be functioning? must she not be functioning? must we not be functioning? must you not be functioning? must they not be functioning?
Perfect
must I not have functioned? must you not have functioned? must she not have functioned? must we not have functioned? must you not have functioned? must they not have functioned?
V-ing perfect
must I not have been functioning? must you not have been functioning? must she not have been functioning? must we not have been functioning? must you not have been functioning? must they not have been functioning?