Several large wooden constructions     1     ( date) back to the Neolithic era（新石器时代) were unearthed at the Jijiaocheng ruins site, a prehistoric cultural site located in Changde City, central China's Hunan Province.

First discovered in 1978,the site used     2     ( be) a city from the Qujialing culture period (3300 BC-2600 BC) - a Neolithic civilization,     3     had roots in the middle and upper reaches of the Yangtze River primarily     4     (find) in today's Hunan and Hubei provinces.

Researchers     5     (conduct) three excavations(挖掘)at the southwestern part of the city wall since 2020. More than 30 housing sites were discovered at the 721 -square-meter area,     6     a number of wooden architectural relics unearthed that were built 4,800 years ago. Researchers think they are the most complete and     7     (early) wooden structure building foundation in China. Besides, remains of rice husks (外壳) were also found at the site, covering     8     area of 80 square meters.

Researchers believe     9     ( strong) the new findings will enrich the architectural history of prehistoric China. " The     10     ( discover) helps us understand the overall architectural style of the Yangtze River Basin," said Zhao Hui, a professor at Peking University School of Archaeology and Museology.