In O'Brien's "The Things They Carried," how is chronology used?
In this opening and title story of O'Brien's anthology, the author sets up a pattern of using flashback chronology and brief interruptions in time. For example, when O'Brien describes Lt. Jimmy Cross and his photo of Martha, he mentions Lt. Cross's routine with the photo, but he interrupts the description with flashbacks in Cross's mind to when he had a date with Martha.
In addition to this interruption technique, O'Brien narrates most of the story in chronological order and includes references to the future, especially about which soldiers do not make it out of the war alive, such as describing what Ted Lavender carries and then stating "but that was before he was shot."
This style of including flashbacks and snippets from earlier or future moments in someone's life is chosen carefully by O'Brien because it represents the mind of someone struggling with traumatic events and trying to create some frame of reference for those events.