A、They are few in numbers. B、They depict important historical events. C、They provide a lot of information about ordinary people.

We usually think of history as the story of important people and events, but some historians are also interested in the daily lives of ordinary people.  We can get this kind of information from written documents like diaries and town records, of course, but strange as this may seem—we can also learn a lot from studying old family portraits. Family portraits provide clues about things like the size of the family and the hobbies and tastes of family members.  The number of children in a portrait, for example, indicates the size of the family; the types of clothing family members wore for the portrait suggest the popular fashions of the time. The objects that children hold in their hands can give clues about the games they played and their hobbies. The background of a family portrait gives historians an idea of room size and furnishings and even the wealth and social position of the family. All of these details help historians understand more about the everyday lives of some of the ordinary people from the past.