I must quiver you must quiver he must quiver we must quiver you must quiver they must quiver
V-ing form
I must be quivering you must be quivering he must be quivering we must be quivering you must be quivering they must be quivering
Perfect
I must have quivered you must have quivered he must have quivered we must have quivered you must have quivered they must have quivered
V-ing perfect
I must have been quivering you must have been quivering he must have been quivering we must have been quivering you must have been quivering they must have been quivering
Negation
Simple form
I must not quiver you must not quiver he must not quiver we must not quiver you must not quiver they must not quiver
V-ing form
I must not be quivering you must not be quivering he must not be quivering we must not be quivering you must not be quivering they must not be quivering
Perfect
I must not have quivered you must not have quivered he must not have quivered we must not have quivered you must not have quivered they must not have quivered
V-ing perfect
I must not have been quivering you must not have been quivering he must not have been quivering we must not have been quivering you must not have been quivering they must not have been quivering
Interrogative form
Simple form
must I quiver? must you quiver? must he quiver? must we quiver? must you quiver? must they quiver?
V-ing form
must I be quivering? must you be quivering? must he be quivering? must we be quivering? must you be quivering? must they be quivering?
Perfect
must I have quivered? must you have quivered? must he have quivered? must we have quivered? must you have quivered? must they have quivered?
V-ing perfect
must I have been quivering? must you have been quivering? must he have been quivering? must we have been quivering? must you have been quivering? must they have been quivering?
Interro-negative form
Simple form
must I not quiver? must you not quiver? must he not quiver? must we not quiver? must you not quiver? must they not quiver?
V-ing form
must I not be quivering? must you not be quivering? must he not be quivering? must we not be quivering? must you not be quivering? must they not be quivering?
Perfect
must I not have quivered? must you not have quivered? must he not have quivered? must we not have quivered? must you not have quivered? must they not have quivered?
V-ing perfect
must I not have been quivering? must you not have been quivering? must he not have been quivering? must we not have been quivering? must you not have been quivering? must they not have been quivering?