English verb conjugation
MUST DECAY

Regular verb: decay - decayed - decayed

Affirmation

Simple form	V-ing form
I must decay you must decay he must decay we must decay you must decay they must decay	I must be decaying you must be decaying he must be decaying we must be decaying you must be decaying they must be decaying
Perfect	V-ing perfect
I must have decayed you must have decayed he must have decayed we must have decayed you must have decayed they must have decayed	I must have been decaying you must have been decaying he must have been decaying we must have been decaying you must have been decaying they must have been decaying

Negation

Simple form	V-ing form
I mustn't decay you mustn't decay he mustn't decay we mustn't decay you mustn't decay they mustn't decay	I mustn't be decaying you mustn't be decaying he mustn't be decaying we mustn't be decaying you mustn't be decaying they mustn't be decaying
Perfect	V-ing perfect
I mustn't have decayed you mustn't have decayed he mustn't have decayed we mustn't have decayed you mustn't have decayed they mustn't have decayed	I mustn't have been decaying you mustn't have been decaying he mustn't have been decaying we mustn't have been decaying you mustn't have been decaying they mustn't have been decaying

Interrogative form

Simple form	V-ing form
must I decay? must you decay? must he decay? must we decay? must you decay? must they decay?	must I be decaying? must you be decaying? must he be decaying? must we be decaying? must you be decaying? must they be decaying?
Perfect	V-ing perfect
must I have decayed? must you have decayed? must he have decayed? must we have decayed? must you have decayed? must they have decayed?	must I have been decaying? must you have been decaying? must he have been decaying? must we have been decaying? must you have been decaying? must they have been decaying?

Interro-negative form

Simple form	V-ing form
mustn't I decay? mustn't you decay? mustn't he decay? mustn't we decay? mustn't you decay? mustn't they decay?	mustn't I be decaying? mustn't you be decaying? mustn't he be decaying? mustn't we be decaying? mustn't you be decaying? mustn't they be decaying?
Perfect	V-ing perfect
mustn't I have decayed? mustn't you have decayed? mustn't he have decayed? mustn't we have decayed? mustn't you have decayed? mustn't they have decayed?	mustn't I have been decaying? mustn't you have been decaying? mustn't he have been decaying? mustn't we have been decaying? mustn't you have been decaying? mustn't they have been decaying?