must burden
Regular verb: burden - burdened- burdened

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must burden
you must burden
he must burden
we must burden
you must burden
they must burden 	I must be burdening
you must be burdening
he must be burdening
we must be burdening
you must be burdening
they must be burdening	I must have burdened
you must have burdened
he must have burdened
we must have burdened
you must have burdened
they must have burdened	I must have been burdening
you must have been burdening
he must have been burdening
we must have been burdening
you must have been burdening
they must have been burdening	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not burden
you must not burden
he must not burden
we must not burden
you must not burden
they must not burden 	I must not be burdening
you must not be burdening
he must not be burdening
we must not be burdening
you must not be burdening
they must not be burdening	I must not have burdened
you must not have burdened
he must not have burdened
we must not have burdened
you must not have burdened
they must not have burdened	I must not have been burdening
you must not have been burdening
he must not have been burdening
we must not have been burdening
you must not have been burdening
they must not have been burdening	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I burden?
must you burden?
must he burden?
must we burden?
must you burden?
must they burden? 	must I be burdening?
must you be burdening?
must he be burdening?
must we be burdening?
must you be burdening?
must they be burdening? 	must I have burdened?
must you have burdened?
must he have burdened?
must we have burdened?
must you have burdened?
must they have burdened? 	must I have been burdening?
must you have been burdening?
must he have been burdening?
must we have been burdening?
must you have been burdening?
must they have been burdening? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not burden?
must you not burden?
must he not burden?
must we not burden?
must you not burden?
must they not burden? 	must I not be burdening?
must you not be burdening?
must he not be burdening?
must we not be burdening?
must you not be burdening?
must they not be burdening? 	must I not have burdened?
must you not have burdened?
must he not have burdened?
must we not have burdened?
must you not have burdened?
must they not have burdened? 	must I not have been burdening?
must you not have been burdening?
must he not have been burdening?
must we not have been burdening?
must you not have been burdening?
must they not have been burdening?