must decrepitate
Regular verb: decrepitate - decrepitated- decrepitated

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must decrepitate
you must decrepitate
he must decrepitate
we must decrepitate
you must decrepitate
they must decrepitate 	I must be decrepitating
you must be decrepitating
he must be decrepitating
we must be decrepitating
you must be decrepitating
they must be decrepitating	I must have decrepitated
you must have decrepitated
he must have decrepitated
we must have decrepitated
you must have decrepitated
they must have decrepitated	I must have been decrepitating
you must have been decrepitating
he must have been decrepitating
we must have been decrepitating
you must have been decrepitating
they must have been decrepitating	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't decrepitate
you mustn't decrepitate
he mustn't decrepitate
we mustn't decrepitate
you mustn't decrepitate
they mustn't decrepitate 	I mustn't be decrepitating
you mustn't be decrepitating
he mustn't be decrepitating
we mustn't be decrepitating
you mustn't be decrepitating
they mustn't be decrepitating	I mustn't have decrepitated
you mustn't have decrepitated
he mustn't have decrepitated
we mustn't have decrepitated
you mustn't have decrepitated
they mustn't have decrepitated	I mustn't have been decrepitating
you mustn't have been decrepitating
he mustn't have been decrepitating
we mustn't have been decrepitating
you mustn't have been decrepitating
they mustn't have been decrepitating	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I decrepitate?
must you decrepitate?
must he decrepitate?
must we decrepitate?
must you decrepitate?
must they decrepitate? 	must I be decrepitating?
must you be decrepitating?
must he be decrepitating?
must we be decrepitating?
must you be decrepitating?
must they be decrepitating? 	must I have decrepitated?
must you have decrepitated?
must he have decrepitated?
must we have decrepitated?
must you have decrepitated?
must they have decrepitated? 	must I have been decrepitating?
must you have been decrepitating?
must he have been decrepitating?
must we have been decrepitating?
must you have been decrepitating?
must they have been decrepitating? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I decrepitate?
mustn't you decrepitate?
mustn't he decrepitate?
mustn't we decrepitate?
mustn't you decrepitate?
mustn't they decrepitate? 	mustn't I be decrepitating?
mustn't you be decrepitating?
mustn't he be decrepitating?
mustn't we be decrepitating?
mustn't you be decrepitating?
mustn't they be decrepitating? 	mustn't I have decrepitated?
mustn't you have decrepitated?
mustn't he have decrepitated?
mustn't we have decrepitated?
mustn't you have decrepitated?
mustn't they have decrepitated? 	mustn't I have been decrepitating?
mustn't you have been decrepitating?
mustn't he have been decrepitating?
mustn't we have been decrepitating?
mustn't you have been decrepitating?
mustn't they have been decrepitating?