I must join you must join she must join we must join you must join they must join
V-ing form
I must be joining you must be joining she must be joining we must be joining you must be joining they must be joining
Perfect
I must have joined you must have joined she must have joined we must have joined you must have joined they must have joined
V-ing perfect
I must have been joining you must have been joining she must have been joining we must have been joining you must have been joining they must have been joining
Negation
Simple form
I must not join you must not join she must not join we must not join you must not join they must not join
V-ing form
I must not be joining you must not be joining she must not be joining we must not be joining you must not be joining they must not be joining
Perfect
I must not have joined you must not have joined she must not have joined we must not have joined you must not have joined they must not have joined
V-ing perfect
I must not have been joining you must not have been joining she must not have been joining we must not have been joining you must not have been joining they must not have been joining
Interrogative form
Simple form
must I join? must you join? must she join? must we join? must you join? must they join?
V-ing form
must I be joining? must you be joining? must she be joining? must we be joining? must you be joining? must they be joining?
Perfect
must I have joined? must you have joined? must she have joined? must we have joined? must you have joined? must they have joined?
V-ing perfect
must I have been joining? must you have been joining? must she have been joining? must we have been joining? must you have been joining? must they have been joining?
Interro-negative form
Simple form
must I not join? must you not join? must she not join? must we not join? must you not join? must they not join?
V-ing form
must I not be joining? must you not be joining? must she not be joining? must we not be joining? must you not be joining? must they not be joining?
Perfect
must I not have joined? must you not have joined? must she not have joined? must we not have joined? must you not have joined? must they not have joined?
V-ing perfect
must I not have been joining? must you not have been joining? must she not have been joining? must we not have been joining? must you not have been joining? must they not have been joining?