I must flutter you must flutter he must flutter we must flutter you must flutter they must flutter
V-ing form
I must be fluttering you must be fluttering he must be fluttering we must be fluttering you must be fluttering they must be fluttering
Perfect
I must have fluttered you must have fluttered he must have fluttered we must have fluttered you must have fluttered they must have fluttered
V-ing perfect
I must have been fluttering you must have been fluttering he must have been fluttering we must have been fluttering you must have been fluttering they must have been fluttering
Negation
Simple form
I must not flutter you must not flutter he must not flutter we must not flutter you must not flutter they must not flutter
V-ing form
I must not be fluttering you must not be fluttering he must not be fluttering we must not be fluttering you must not be fluttering they must not be fluttering
Perfect
I must not have fluttered you must not have fluttered he must not have fluttered we must not have fluttered you must not have fluttered they must not have fluttered
V-ing perfect
I must not have been fluttering you must not have been fluttering he must not have been fluttering we must not have been fluttering you must not have been fluttering they must not have been fluttering
Interrogative form
Simple form
must I flutter? must you flutter? must he flutter? must we flutter? must you flutter? must they flutter?
V-ing form
must I be fluttering? must you be fluttering? must he be fluttering? must we be fluttering? must you be fluttering? must they be fluttering?
Perfect
must I have fluttered? must you have fluttered? must he have fluttered? must we have fluttered? must you have fluttered? must they have fluttered?
V-ing perfect
must I have been fluttering? must you have been fluttering? must he have been fluttering? must we have been fluttering? must you have been fluttering? must they have been fluttering?
Interro-negative form
Simple form
must I not flutter? must you not flutter? must he not flutter? must we not flutter? must you not flutter? must they not flutter?
V-ing form
must I not be fluttering? must you not be fluttering? must he not be fluttering? must we not be fluttering? must you not be fluttering? must they not be fluttering?
Perfect
must I not have fluttered? must you not have fluttered? must he not have fluttered? must we not have fluttered? must you not have fluttered? must they not have fluttered?
V-ing perfect
must I not have been fluttering? must you not have been fluttering? must he not have been fluttering? must we not have been fluttering? must you not have been fluttering? must they not have been fluttering?