I must buffer you must buffer he must buffer we must buffer you must buffer they must buffer
V-ing form
I must be buffering you must be buffering he must be buffering we must be buffering you must be buffering they must be buffering
Perfect
I must have buffered you must have buffered he must have buffered we must have buffered you must have buffered they must have buffered
V-ing perfect
I must have been buffering you must have been buffering he must have been buffering we must have been buffering you must have been buffering they must have been buffering
Negation
Simple form
I mustn't buffer you mustn't buffer he mustn't buffer we mustn't buffer you mustn't buffer they mustn't buffer
V-ing form
I mustn't be buffering you mustn't be buffering he mustn't be buffering we mustn't be buffering you mustn't be buffering they mustn't be buffering
Perfect
I mustn't have buffered you mustn't have buffered he mustn't have buffered we mustn't have buffered you mustn't have buffered they mustn't have buffered
V-ing perfect
I mustn't have been buffering you mustn't have been buffering he mustn't have been buffering we mustn't have been buffering you mustn't have been buffering they mustn't have been buffering
Interrogative form
Simple form
must I buffer? must you buffer? must he buffer? must we buffer? must you buffer? must they buffer?
V-ing form
must I be buffering? must you be buffering? must he be buffering? must we be buffering? must you be buffering? must they be buffering?
Perfect
must I have buffered? must you have buffered? must he have buffered? must we have buffered? must you have buffered? must they have buffered?
V-ing perfect
must I have been buffering? must you have been buffering? must he have been buffering? must we have been buffering? must you have been buffering? must they have been buffering?
Interro-negative form
Simple form
mustn't I buffer? mustn't you buffer? mustn't he buffer? mustn't we buffer? mustn't you buffer? mustn't they buffer?
V-ing form
mustn't I be buffering? mustn't you be buffering? mustn't he be buffering? mustn't we be buffering? mustn't you be buffering? mustn't they be buffering?
Perfect
mustn't I have buffered? mustn't you have buffered? mustn't he have buffered? mustn't we have buffered? mustn't you have buffered? mustn't they have buffered?
V-ing perfect
mustn't I have been buffering? mustn't you have been buffering? mustn't he have been buffering? mustn't we have been buffering? mustn't you have been buffering? mustn't they have been buffering?