must muscle
Regular verb: muscle - muscled- muscled

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must muscle
you must muscle
he must muscle
we must muscle
you must muscle
they must muscle 	I must be muscling
you must be muscling
he must be muscling
we must be muscling
you must be muscling
they must be muscling	I must have muscled
you must have muscled
he must have muscled
we must have muscled
you must have muscled
they must have muscled	I must have been muscling
you must have been muscling
he must have been muscling
we must have been muscling
you must have been muscling
they must have been muscling	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not muscle
you must not muscle
he must not muscle
we must not muscle
you must not muscle
they must not muscle 	I must not be muscling
you must not be muscling
he must not be muscling
we must not be muscling
you must not be muscling
they must not be muscling	I must not have muscled
you must not have muscled
he must not have muscled
we must not have muscled
you must not have muscled
they must not have muscled	I must not have been muscling
you must not have been muscling
he must not have been muscling
we must not have been muscling
you must not have been muscling
they must not have been muscling	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I muscle?
must you muscle?
must he muscle?
must we muscle?
must you muscle?
must they muscle? 	must I be muscling?
must you be muscling?
must he be muscling?
must we be muscling?
must you be muscling?
must they be muscling? 	must I have muscled?
must you have muscled?
must he have muscled?
must we have muscled?
must you have muscled?
must they have muscled? 	must I have been muscling?
must you have been muscling?
must he have been muscling?
must we have been muscling?
must you have been muscling?
must they have been muscling? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not muscle?
must you not muscle?
must he not muscle?
must we not muscle?
must you not muscle?
must they not muscle? 	must I not be muscling?
must you not be muscling?
must he not be muscling?
must we not be muscling?
must you not be muscling?
must they not be muscling? 	must I not have muscled?
must you not have muscled?
must he not have muscled?
must we not have muscled?
must you not have muscled?
must they not have muscled? 	must I not have been muscling?
must you not have been muscling?
must he not have been muscling?
must we not have been muscling?
must you not have been muscling?
must they not have been muscling?