must decompose
Regular verb: decompose - decomposed- decomposed

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must decompose
you must decompose
he must decompose
we must decompose
you must decompose
they must decompose 	I must be decomposing
you must be decomposing
he must be decomposing
we must be decomposing
you must be decomposing
they must be decomposing	I must have decomposed
you must have decomposed
he must have decomposed
we must have decomposed
you must have decomposed
they must have decomposed	I must have been decomposing
you must have been decomposing
he must have been decomposing
we must have been decomposing
you must have been decomposing
they must have been decomposing	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't decompose
you mustn't decompose
he mustn't decompose
we mustn't decompose
you mustn't decompose
they mustn't decompose 	I mustn't be decomposing
you mustn't be decomposing
he mustn't be decomposing
we mustn't be decomposing
you mustn't be decomposing
they mustn't be decomposing	I mustn't have decomposed
you mustn't have decomposed
he mustn't have decomposed
we mustn't have decomposed
you mustn't have decomposed
they mustn't have decomposed	I mustn't have been decomposing
you mustn't have been decomposing
he mustn't have been decomposing
we mustn't have been decomposing
you mustn't have been decomposing
they mustn't have been decomposing	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I decompose?
must you decompose?
must he decompose?
must we decompose?
must you decompose?
must they decompose? 	must I be decomposing?
must you be decomposing?
must he be decomposing?
must we be decomposing?
must you be decomposing?
must they be decomposing? 	must I have decomposed?
must you have decomposed?
must he have decomposed?
must we have decomposed?
must you have decomposed?
must they have decomposed? 	must I have been decomposing?
must you have been decomposing?
must he have been decomposing?
must we have been decomposing?
must you have been decomposing?
must they have been decomposing? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I decompose?
mustn't you decompose?
mustn't he decompose?
mustn't we decompose?
mustn't you decompose?
mustn't they decompose? 	mustn't I be decomposing?
mustn't you be decomposing?
mustn't he be decomposing?
mustn't we be decomposing?
mustn't you be decomposing?
mustn't they be decomposing? 	mustn't I have decomposed?
mustn't you have decomposed?
mustn't he have decomposed?
mustn't we have decomposed?
mustn't you have decomposed?
mustn't they have decomposed? 	mustn't I have been decomposing?
mustn't you have been decomposing?
mustn't he have been decomposing?
mustn't we have been decomposing?
mustn't you have been decomposing?
mustn't they have been decomposing?