I must answer you must answer he must answer we must answer you must answer they must answer
V-ing form
I must be answering you must be answering he must be answering we must be answering you must be answering they must be answering
Perfect
I must have answered you must have answered he must have answered we must have answered you must have answered they must have answered
V-ing perfect
I must have been answering you must have been answering he must have been answering we must have been answering you must have been answering they must have been answering
Negation
Simple form
I must not answer you must not answer he must not answer we must not answer you must not answer they must not answer
V-ing form
I must not be answering you must not be answering he must not be answering we must not be answering you must not be answering they must not be answering
Perfect
I must not have answered you must not have answered he must not have answered we must not have answered you must not have answered they must not have answered
V-ing perfect
I must not have been answering you must not have been answering he must not have been answering we must not have been answering you must not have been answering they must not have been answering
Interrogative form
Simple form
must I answer? must you answer? must he answer? must we answer? must you answer? must they answer?
V-ing form
must I be answering? must you be answering? must he be answering? must we be answering? must you be answering? must they be answering?
Perfect
must I have answered? must you have answered? must he have answered? must we have answered? must you have answered? must they have answered?
V-ing perfect
must I have been answering? must you have been answering? must he have been answering? must we have been answering? must you have been answering? must they have been answering?
Interro-negative form
Simple form
must I not answer? must you not answer? must he not answer? must we not answer? must you not answer? must they not answer?
V-ing form
must I not be answering? must you not be answering? must he not be answering? must we not be answering? must you not be answering? must they not be answering?
Perfect
must I not have answered? must you not have answered? must he not have answered? must we not have answered? must you not have answered? must they not have answered?
V-ing perfect
must I not have been answering? must you not have been answering? must he not have been answering? must we not have been answering? must you not have been answering? must they not have been answering?