English verb conjugation
MUST DUCK

Regular verb: duck - ducked - ducked

Affirmation

Simple form	V-ing form
I must duck you must duck she must duck we must duck you must duck they must duck	I must be ducking you must be ducking she must be ducking we must be ducking you must be ducking they must be ducking
Perfect	V-ing perfect
I must have ducked you must have ducked she must have ducked we must have ducked you must have ducked they must have ducked	I must have been ducking you must have been ducking she must have been ducking we must have been ducking you must have been ducking they must have been ducking

Negation

Simple form	V-ing form
I mustn't duck you mustn't duck she mustn't duck we mustn't duck you mustn't duck they mustn't duck	I mustn't be ducking you mustn't be ducking she mustn't be ducking we mustn't be ducking you mustn't be ducking they mustn't be ducking
Perfect	V-ing perfect
I mustn't have ducked you mustn't have ducked she mustn't have ducked we mustn't have ducked you mustn't have ducked they mustn't have ducked	I mustn't have been ducking you mustn't have been ducking she mustn't have been ducking we mustn't have been ducking you mustn't have been ducking they mustn't have been ducking

Interrogative form

Simple form	V-ing form
must I duck? must you duck? must she duck? must we duck? must you duck? must they duck?	must I be ducking? must you be ducking? must she be ducking? must we be ducking? must you be ducking? must they be ducking?
Perfect	V-ing perfect
must I have ducked? must you have ducked? must she have ducked? must we have ducked? must you have ducked? must they have ducked?	must I have been ducking? must you have been ducking? must she have been ducking? must we have been ducking? must you have been ducking? must they have been ducking?

Interro-negative form

Simple form	V-ing form
mustn't I duck? mustn't you duck? mustn't she duck? mustn't we duck? mustn't you duck? mustn't they duck?	mustn't I be ducking? mustn't you be ducking? mustn't she be ducking? mustn't we be ducking? mustn't you be ducking? mustn't they be ducking?
Perfect	V-ing perfect
mustn't I have ducked? mustn't you have ducked? mustn't she have ducked? mustn't we have ducked? mustn't you have ducked? mustn't they have ducked?	mustn't I have been ducking? mustn't you have been ducking? mustn't she have been ducking? mustn't we have been ducking? mustn't you have been ducking? mustn't they have been ducking?