English verb conjugation
MUST RETRIEVE

Regular verb: retrieve - retrieved - retrieved

Affirmation

Simple form	V-ing form
I must retrieve you must retrieve he must retrieve we must retrieve you must retrieve they must retrieve	I must be retrieving you must be retrieving he must be retrieving we must be retrieving you must be retrieving they must be retrieving
Perfect	V-ing perfect
I must have retrieved you must have retrieved he must have retrieved we must have retrieved you must have retrieved they must have retrieved	I must have been retrieving you must have been retrieving he must have been retrieving we must have been retrieving you must have been retrieving they must have been retrieving

Negation

Simple form	V-ing form
I must not retrieve you must not retrieve he must not retrieve we must not retrieve you must not retrieve they must not retrieve	I must not be retrieving you must not be retrieving he must not be retrieving we must not be retrieving you must not be retrieving they must not be retrieving
Perfect	V-ing perfect
I must not have retrieved you must not have retrieved he must not have retrieved we must not have retrieved you must not have retrieved they must not have retrieved	I must not have been retrieving you must not have been retrieving he must not have been retrieving we must not have been retrieving you must not have been retrieving they must not have been retrieving

Interrogative form

Simple form	V-ing form
must I retrieve? must you retrieve? must he retrieve? must we retrieve? must you retrieve? must they retrieve?	must I be retrieving? must you be retrieving? must he be retrieving? must we be retrieving? must you be retrieving? must they be retrieving?
Perfect	V-ing perfect
must I have retrieved? must you have retrieved? must he have retrieved? must we have retrieved? must you have retrieved? must they have retrieved?	must I have been retrieving? must you have been retrieving? must he have been retrieving? must we have been retrieving? must you have been retrieving? must they have been retrieving?

Interro-negative form

Simple form	V-ing form
must I not retrieve? must you not retrieve? must he not retrieve? must we not retrieve? must you not retrieve? must they not retrieve?	must I not be retrieving? must you not be retrieving? must he not be retrieving? must we not be retrieving? must you not be retrieving? must they not be retrieving?
Perfect	V-ing perfect
must I not have retrieved? must you not have retrieved? must he not have retrieved? must we not have retrieved? must you not have retrieved? must they not have retrieved?	must I not have been retrieving? must you not have been retrieving? must he not have been retrieving? must we not have been retrieving? must you not have been retrieving? must they not have been retrieving?