must descend
Regular verb: descend - descended- descended

Affirmation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must descend
you must descend
he must descend
we must descend
you must descend
they must descend 	I must be descending
you must be descending
he must be descending
we must be descending
you must be descending
they must be descending	I must have descended
you must have descended
he must have descended
we must have descended
you must have descended
they must have descended	I must have been descending
you must have been descending
he must have been descending
we must have been descending
you must have been descending
they must have been descending	

Negation 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
I must not descend
you must not descend
he must not descend
we must not descend
you must not descend
they must not descend 	I must not be descending
you must not be descending
he must not be descending
we must not be descending
you must not be descending
they must not be descending	I must not have descended
you must not have descended
he must not have descended
we must not have descended
you must not have descended
they must not have descended	I must not have been descending
you must not have been descending
he must not have been descending
we must not have been descending
you must not have been descending
they must not have been descending	

Interrogative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I descend?
must you descend?
must he descend?
must we descend?
must you descend?
must they descend? 	must I be descending?
must you be descending?
must he be descending?
must we be descending?
must you be descending?
must they be descending? 	must I have descended?
must you have descended?
must he have descended?
must we have descended?
must you have descended?
must they have descended? 	must I have been descending?
must you have been descending?
must he have been descending?
must we have been descending?
must you have been descending?
must they have been descending? 	

Interro-negative form 	
Simple form 	V-ing form 	Perfect 	V-ing perfect 	
must I not descend?
must you not descend?
must he not descend?
must we not descend?
must you not descend?
must they not descend? 	must I not be descending?
must you not be descending?
must he not be descending?
must we not be descending?
must you not be descending?
must they not be descending? 	must I not have descended?
must you not have descended?
must he not have descended?
must we not have descended?
must you not have descended?
must they not have descended? 	must I not have been descending?
must you not have been descending?
must he not have been descending?
must we not have been descending?
must you not have been descending?
must they not have been descending?