How did the ancient Chinese keep food warm in winter? Facilities like electric rice cookers, microwaves, and electric kettles, make it easy for people to keep food warm and enjoy a comfortable winter. So how did Chinese people in ancient times keep food warm in winter without these? In fact, ancient Chinese people used their own methods of heat preservation as early as the Shang and Zhou dynasties. * "Wen Ding", ancient rice cooker One of the major functions of an electric rice cooker is to keep food warm. The "Wen Ding", an ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container preserved heart by burning fuels like charcoal. The "Wen Ding" unearthed in Nanjing in 1989 is thought to be the oldest of its kind discovered in China, dating back to the Stone Age, The craftsmanship of making the "Wen Ding" was developed in the Bronze Age. The bronze Ding from Shang and Zhou dynasties took on different shapes and structures. * "Ran LU", ancient small hot pot The "Ran LU" is a small size cooking vessel  made of bronze, which can be divided into three parts. A charcoal stove forms the main structure, with a bottom tray to hold charcoal ashes, and a movable cup at the top. Some experts have concluded that the vessel's structure suggests it may have been used as a small hot pot and that these vessels became popular in the Warring States Period(475--221 BC) *Bronze You, ancient kettle The Bronze You was one of the most common wine containers during the Shang and Zhou dynasties. The Bronze You can also be used to warm wine. For example, the Bronze You with beast mask design, unearthed in Jiangxi province, has an opening where charcoals could be placed. Just as people today can't do without an electric kettle, the Bronze You allowed people to enjoy a hot drink. *Bronze Yan, ancient steamer Although the "Wen Ding" was effective at keeping food warm, the ancient Chinese people later found that its burning produced pollution. As a result, the Bronze Yan was made with a two-tier structure and used to steam rice and other grains. After the Eastern Han Dynasty (AD 25-AD 220), further improvements to the Bronze Yan led to the modern-day steamer. What is the unique advantage of the Bronze Yan?
It is warm. It is convenient. It is environment-friendly. It is useful.
Question: How did the ancient Chinese keep food warm in winter? Facilities like electric rice cookers, microwaves, and electric kettles, make it easy for people to keep food warm and enjoy a comfortable winter. So how did Chinese people in ancient times keep food warm in winter without these? In fact, ancient Chinese people used their own methods of heat preservation as early as the Shang and Zhou dynasties. * "Wen Ding", ancient rice cooker One of the major functions of an electric rice cooker is to keep food warm. The "Wen Ding", an ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container, served the same purpose, but instead of using electric energy, the ancient cooking container preserved heart by burning fuels like charcoal. The "Wen Ding" unearthed in Nanjing in 1989 is thought to be the oldest of its kind discovered in China, dating back to the Stone Age, The craftsmanship of making the "Wen Ding" was developed in the Bronze Age. The bronze Ding from Shang and Zhou dynasties took on different shapes and structures. * "Ran LU", ancient small hot pot The "Ran LU" is a small size cooking vessel  made of bronze, which can be divided into three parts. A charcoal stove forms the main structure, with a bottom tray to hold charcoal ashes, and a movable cup at the top. Some experts have concluded that the vessel's structure suggests it may have been used as a small hot pot and that these vessels became popular in the Warring States Period(475--221 BC) *Bronze You, ancient kettle The Bronze You was one of the most common wine containers during the Shang and Zhou dynasties. The Bronze You can also be used to warm wine. For example, the Bronze You with beast mask design, unearthed in Jiangxi province, has an opening where charcoals could be placed. Just as people today can't do without an electric kettle, the Bronze You allowed people to enjoy a hot drink. *Bronze Yan, ancient steamer Although the "Wen Ding" was effective at keeping food warm, the ancient Chinese people later found that its burning produced pollution. As a result, the Bronze Yan was made with a two-tier structure and used to steam rice and other grains. After the Eastern Han Dynasty (AD 25-AD 220), further improvements to the Bronze Yan led to the modern-day steamer. What is the unique advantage of the Bronze Yan?
A. It is warm.
B. It is convenient.
C. It is environment-friendly.
D. It is useful.
Answer: