Complex sentence: Dr. Mirranay worked as a Medical Officer in Afghani refugee camps in Pakistan from 1980--1986 for the United Nations, providing humanitarian assistance to Afghan refugees, particularly in the fields of health care and medical education.
Split into simpler sentences: Dr. Mirranay worked as a Medical Officer in Afghani refugee camps in Pakistan from 1980--1986 for the United Nations. Which which provided humanitarian assistance to Afghan refugees, particularly in the fields of health care and medical education.