must clump
Regular verb: clump - clumped- clumped

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must clump
you must clump
he must clump
we must clump
you must clump
they must clump 	I must be clumping
you must be clumping
he must be clumping
we must be clumping
you must be clumping
they must be clumping	I must have clumped
you must have clumped
he must have clumped
we must have clumped
you must have clumped
they must have clumped	I must have been clumping
you must have been clumping
he must have been clumping
we must have been clumping
you must have been clumping
they must have been clumping	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I mustn't clump
you mustn't clump
he mustn't clump
we mustn't clump
you mustn't clump
they mustn't clump 	I mustn't be clumping
you mustn't be clumping
he mustn't be clumping
we mustn't be clumping
you mustn't be clumping
they mustn't be clumping	I mustn't have clumped
you mustn't have clumped
he mustn't have clumped
we mustn't have clumped
you mustn't have clumped
they mustn't have clumped	I mustn't have been clumping
you mustn't have been clumping
he mustn't have been clumping
we mustn't have been clumping
you mustn't have been clumping
they mustn't have been clumping	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I clump?
must you clump?
must he clump?
must we clump?
must you clump?
must they clump? 	must I be clumping?
must you be clumping?
must he be clumping?
must we be clumping?
must you be clumping?
must they be clumping? 	must I have clumped?
must you have clumped?
must he have clumped?
must we have clumped?
must you have clumped?
must they have clumped? 	must I have been clumping?
must you have been clumping?
must he have been clumping?
must we have been clumping?
must you have been clumping?
must they have been clumping? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
mustn't I clump?
mustn't you clump?
mustn't he clump?
mustn't we clump?
mustn't you clump?
mustn't they clump? 	mustn't I be clumping?
mustn't you be clumping?
mustn't he be clumping?
mustn't we be clumping?
mustn't you be clumping?
mustn't they be clumping? 	mustn't I have clumped?
mustn't you have clumped?
mustn't he have clumped?
mustn't we have clumped?
mustn't you have clumped?
mustn't they have clumped? 	mustn't I have been clumping?
mustn't you have been clumping?
mustn't he have been clumping?
mustn't we have been clumping?
mustn't you have been clumping?
mustn't they have been clumping?