I must fix you must fix he must fix we must fix you must fix they must fix
V-ing form
I must be fixing you must be fixing he must be fixing we must be fixing you must be fixing they must be fixing
Perfect
I must have fixed you must have fixed he must have fixed we must have fixed you must have fixed they must have fixed
V-ing perfect
I must have been fixing you must have been fixing he must have been fixing we must have been fixing you must have been fixing they must have been fixing
Negation
Simple form
I must not fix you must not fix he must not fix we must not fix you must not fix they must not fix
V-ing form
I must not be fixing you must not be fixing he must not be fixing we must not be fixing you must not be fixing they must not be fixing
Perfect
I must not have fixed you must not have fixed he must not have fixed we must not have fixed you must not have fixed they must not have fixed
V-ing perfect
I must not have been fixing you must not have been fixing he must not have been fixing we must not have been fixing you must not have been fixing they must not have been fixing
Interrogative form
Simple form
must I fix? must you fix? must he fix? must we fix? must you fix? must they fix?
V-ing form
must I be fixing? must you be fixing? must he be fixing? must we be fixing? must you be fixing? must they be fixing?
Perfect
must I have fixed? must you have fixed? must he have fixed? must we have fixed? must you have fixed? must they have fixed?
V-ing perfect
must I have been fixing? must you have been fixing? must he have been fixing? must we have been fixing? must you have been fixing? must they have been fixing?
Interro-negative form
Simple form
must I not fix? must you not fix? must he not fix? must we not fix? must you not fix? must they not fix?
V-ing form
must I not be fixing? must you not be fixing? must he not be fixing? must we not be fixing? must you not be fixing? must they not be fixing?
Perfect
must I not have fixed? must you not have fixed? must he not have fixed? must we not have fixed? must you not have fixed? must they not have fixed?
V-ing perfect
must I not have been fixing? must you not have been fixing? must he not have been fixing? must we not have been fixing? must you not have been fixing? must they not have been fixing?