English verb conjugation
MUST VARY

Regular verb: vary - varied - varied

Affirmation

Simple form	V-ing form
I must vary you must vary he must vary we must vary you must vary they must vary	I must be varying you must be varying he must be varying we must be varying you must be varying they must be varying
Perfect	V-ing perfect
I must have varied you must have varied he must have varied we must have varied you must have varied they must have varied	I must have been varying you must have been varying he must have been varying we must have been varying you must have been varying they must have been varying

Negation

Simple form	V-ing form
I mustn't vary you mustn't vary he mustn't vary we mustn't vary you mustn't vary they mustn't vary	I mustn't be varying you mustn't be varying he mustn't be varying we mustn't be varying you mustn't be varying they mustn't be varying
Perfect	V-ing perfect
I mustn't have varied you mustn't have varied he mustn't have varied we mustn't have varied you mustn't have varied they mustn't have varied	I mustn't have been varying you mustn't have been varying he mustn't have been varying we mustn't have been varying you mustn't have been varying they mustn't have been varying

Interrogative form

Simple form	V-ing form
must I vary? must you vary? must he vary? must we vary? must you vary? must they vary?	must I be varying? must you be varying? must he be varying? must we be varying? must you be varying? must they be varying?
Perfect	V-ing perfect
must I have varied? must you have varied? must he have varied? must we have varied? must you have varied? must they have varied?	must I have been varying? must you have been varying? must he have been varying? must we have been varying? must you have been varying? must they have been varying?

Interro-negative form

Simple form	V-ing form
mustn't I vary? mustn't you vary? mustn't he vary? mustn't we vary? mustn't you vary? mustn't they vary?	mustn't I be varying? mustn't you be varying? mustn't he be varying? mustn't we be varying? mustn't you be varying? mustn't they be varying?
Perfect	V-ing perfect
mustn't I have varied? mustn't you have varied? mustn't he have varied? mustn't we have varied? mustn't you have varied? mustn't they have varied?	mustn't I have been varying? mustn't you have been varying? mustn't he have been varying? mustn't we have been varying? mustn't you have been varying? mustn't they have been varying?