English verb conjugation
MUST DECREASE

Regular verb: decrease - decreased - decreased

Affirmation

Simple form	V-ing form
I must decrease you must decrease he must decrease we must decrease you must decrease they must decrease	I must be decreasing you must be decreasing he must be decreasing we must be decreasing you must be decreasing they must be decreasing
Perfect	V-ing perfect
I must have decreased you must have decreased he must have decreased we must have decreased you must have decreased they must have decreased	I must have been decreasing you must have been decreasing he must have been decreasing we must have been decreasing you must have been decreasing they must have been decreasing

Negation

Simple form	V-ing form
I mustn't decrease you mustn't decrease he mustn't decrease we mustn't decrease you mustn't decrease they mustn't decrease	I mustn't be decreasing you mustn't be decreasing he mustn't be decreasing we mustn't be decreasing you mustn't be decreasing they mustn't be decreasing
Perfect	V-ing perfect
I mustn't have decreased you mustn't have decreased he mustn't have decreased we mustn't have decreased you mustn't have decreased they mustn't have decreased	I mustn't have been decreasing you mustn't have been decreasing he mustn't have been decreasing we mustn't have been decreasing you mustn't have been decreasing they mustn't have been decreasing

Interrogative form

Simple form	V-ing form
must I decrease? must you decrease? must he decrease? must we decrease? must you decrease? must they decrease?	must I be decreasing? must you be decreasing? must he be decreasing? must we be decreasing? must you be decreasing? must they be decreasing?
Perfect	V-ing perfect
must I have decreased? must you have decreased? must he have decreased? must we have decreased? must you have decreased? must they have decreased?	must I have been decreasing? must you have been decreasing? must he have been decreasing? must we have been decreasing? must you have been decreasing? must they have been decreasing?

Interro-negative form

Simple form	V-ing form
mustn't I decrease? mustn't you decrease? mustn't he decrease? mustn't we decrease? mustn't you decrease? mustn't they decrease?	mustn't I be decreasing? mustn't you be decreasing? mustn't he be decreasing? mustn't we be decreasing? mustn't you be decreasing? mustn't they be decreasing?
Perfect	V-ing perfect
mustn't I have decreased? mustn't you have decreased? mustn't he have decreased? mustn't we have decreased? mustn't you have decreased? mustn't they have decreased?	mustn't I have been decreasing? mustn't you have been decreasing? mustn't he have been decreasing? mustn't we have been decreasing? mustn't you have been decreasing? mustn't they have been decreasing?