English verb conjugation
MUST CASE

Regular verb: case - cased - cased

Affirmation

Simple form	V-ing form
I must case you must case he must case we must case you must case they must case	I must be casing you must be casing he must be casing we must be casing you must be casing they must be casing
Perfect	V-ing perfect
I must have cased you must have cased he must have cased we must have cased you must have cased they must have cased	I must have been casing you must have been casing he must have been casing we must have been casing you must have been casing they must have been casing

Negation

Simple form	V-ing form
I mustn't case you mustn't case he mustn't case we mustn't case you mustn't case they mustn't case	I mustn't be casing you mustn't be casing he mustn't be casing we mustn't be casing you mustn't be casing they mustn't be casing
Perfect	V-ing perfect
I mustn't have cased you mustn't have cased he mustn't have cased we mustn't have cased you mustn't have cased they mustn't have cased	I mustn't have been casing you mustn't have been casing he mustn't have been casing we mustn't have been casing you mustn't have been casing they mustn't have been casing

Interrogative form

Simple form	V-ing form
must I case? must you case? must he case? must we case? must you case? must they case?	must I be casing? must you be casing? must he be casing? must we be casing? must you be casing? must they be casing?
Perfect	V-ing perfect
must I have cased? must you have cased? must he have cased? must we have cased? must you have cased? must they have cased?	must I have been casing? must you have been casing? must he have been casing? must we have been casing? must you have been casing? must they have been casing?

Interro-negative form

Simple form	V-ing form
mustn't I case? mustn't you case? mustn't he case? mustn't we case? mustn't you case? mustn't they case?	mustn't I be casing? mustn't you be casing? mustn't he be casing? mustn't we be casing? mustn't you be casing? mustn't they be casing?
Perfect	V-ing perfect
mustn't I have cased? mustn't you have cased? mustn't he have cased? mustn't we have cased? mustn't you have cased? mustn't they have cased?	mustn't I have been casing? mustn't you have been casing? mustn't he have been casing? mustn't we have been casing? mustn't you have been casing? mustn't they have been casing?