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