I must goof you must goof he must goof we must goof you must goof they must goof
V-ing form
I must be goofing you must be goofing he must be goofing we must be goofing you must be goofing they must be goofing
Perfect
I must have goofed you must have goofed he must have goofed we must have goofed you must have goofed they must have goofed
V-ing perfect
I must have been goofing you must have been goofing he must have been goofing we must have been goofing you must have been goofing they must have been goofing
Negation
Simple form
I must not goof you must not goof he must not goof we must not goof you must not goof they must not goof
V-ing form
I must not be goofing you must not be goofing he must not be goofing we must not be goofing you must not be goofing they must not be goofing
Perfect
I must not have goofed you must not have goofed he must not have goofed we must not have goofed you must not have goofed they must not have goofed
V-ing perfect
I must not have been goofing you must not have been goofing he must not have been goofing we must not have been goofing you must not have been goofing they must not have been goofing
Interrogative form
Simple form
must I goof? must you goof? must he goof? must we goof? must you goof? must they goof?
V-ing form
must I be goofing? must you be goofing? must he be goofing? must we be goofing? must you be goofing? must they be goofing?
Perfect
must I have goofed? must you have goofed? must he have goofed? must we have goofed? must you have goofed? must they have goofed?
V-ing perfect
must I have been goofing? must you have been goofing? must he have been goofing? must we have been goofing? must you have been goofing? must they have been goofing?
Interro-negative form
Simple form
must I not goof? must you not goof? must he not goof? must we not goof? must you not goof? must they not goof?
V-ing form
must I not be goofing? must you not be goofing? must he not be goofing? must we not be goofing? must you not be goofing? must they not be goofing?
Perfect
must I not have goofed? must you not have goofed? must he not have goofed? must we not have goofed? must you not have goofed? must they not have goofed?
V-ing perfect
must I not have been goofing? must you not have been goofing? must he not have been goofing? must we not have been goofing? must you not have been goofing? must they not have been goofing?