I must fight you must fight she must fight we must fight you must fight they must fight
V-ing form
I must be fighting you must be fighting she must be fighting we must be fighting you must be fighting they must be fighting
Perfect
I must have fought you must have fought she must have fought we must have fought you must have fought they must have fought
V-ing perfect
I must have been fighting you must have been fighting she must have been fighting we must have been fighting you must have been fighting they must have been fighting
Negation
Simple form
I must not fight you must not fight she must not fight we must not fight you must not fight they must not fight
V-ing form
I must not be fighting you must not be fighting she must not be fighting we must not be fighting you must not be fighting they must not be fighting
Perfect
I must not have fought you must not have fought she must not have fought we must not have fought you must not have fought they must not have fought
V-ing perfect
I must not have been fighting you must not have been fighting she must not have been fighting we must not have been fighting you must not have been fighting they must not have been fighting
Interrogative form
Simple form
must I fight? must you fight? must she fight? must we fight? must you fight? must they fight?
V-ing form
must I be fighting? must you be fighting? must she be fighting? must we be fighting? must you be fighting? must they be fighting?
Perfect
must I have fought? must you have fought? must she have fought? must we have fought? must you have fought? must they have fought?
V-ing perfect
must I have been fighting? must you have been fighting? must she have been fighting? must we have been fighting? must you have been fighting? must they have been fighting?
Interro-negative form
Simple form
must I not fight? must you not fight? must she not fight? must we not fight? must you not fight? must they not fight?
V-ing form
must I not be fighting? must you not be fighting? must she not be fighting? must we not be fighting? must you not be fighting? must they not be fighting?
Perfect
must I not have fought? must you not have fought? must she not have fought? must we not have fought? must you not have fought? must they not have fought?
V-ing perfect
must I not have been fighting? must you not have been fighting? must she not have been fighting? must we not have been fighting? must you not have been fighting? must they not have been fighting?