Excuse me, there is common sense about history

Centuries are all added to the back, for example, the 60s of the first century AD is the period from 60 AD to 69 AD.

Century. A century is a hundred years and usually refers to a continuous hundred years. When used to calculate days, the century usually begins with an era divisible by 100 or a year thereafter, such as 2000 or 2001.

This odd-numbered chronology comes from the post-Jesus era, where 1 year usually means "year of our lord", so the first century runs from 1 AD to 100 AD, and the 20th century runs from 1901 AD to 2000 AD, so 2001 is the first year of the 21st century. However, the first century has been set at 99 years AD, while the following centuries will be 100 years, and if this definition is followed, 2000 will be the first year of the twenty-first century.

Age. Chronology, an era is a decade, which refers to consecutive ten years, and is usually applied to the year of the Common Era. The chronology is divided into:

According to the A.D. year, the decade adjacent to the year in which it is divisible by 10 is an epoch. For example, in the sixties of the twentieth century, it usually refers to the 10 consecutive years from 1960 to 1969, but it is also believed that it should refer to the 10 consecutive years from 1961 to 1970.

The sixties refer to the years 60 to 69. The year of Jesus' birth is known as the first year of the Common Era, and from now until 99 the first century is known as the first century of the Common Era, and so on. Therefore, the nineteenth century refers to the period from 1801 to 1899.

This is one of the divisions, and some reference books also say that it is 100 years) As for BC, it is enough to look at the number axis symmetrically. For example, Confucius (551 BC) was in the middle of the sixth century BC.

The Common Era is marked by the year of Jesus' birth, which is equivalent to the zero point in the number line. The first century refers to the period from 0 to 100 AD, and so on from the 19th century to 1800-1900.

For example, 1751 is the 50s of the 18th century, the first two numbers plus one is the world, the back 50-59 is the 50s, and now it is 2014 is the 10s of the 21st century.

We are now in the 21st century.

AD 0001-0100 is the 1st century.

1801-1900 was the 19th century.

There is a theory that 0000-0099 is the 1st century, but there is no 0000 AD).

3. History is the proof of the prosperity and decline of a nation, just like a mirror, no matter what the people in front of him did right or wrong, he can give a fair evaluation. Moreover, history also embodies the wisdom of the ancient people of our country. Therefore, in order to understand China, it is necessary to understand China's historical development, because China's history has been passed down and influenced the thinking of several generations.

In the Xia Dynasty, wine and the summer calendar were invented. The summer calendar was invented according to the direction of the Big Dipper, which is what we call the lunar calendar, which is still used today!

The Shang Dynasty was founded by the Shang tribes in the middle and lower reaches of the Yellow River, and the first emperor was Shang Tang. On the basis of the original Xia Dynasty, the Shang Dynasty expanded some territory, from Liaoning in the north, to Shaanxi in the west to the Bohai Sea in the west, and there were many vassal territories called Fang Guo around.

The coins of the Shang Dynasty are very special, they are shells, which are also the earliest currencies in China.

After King Wu of Zhou defeated King Shang and established the Zhou Dynasty, the Zhou Dynasty was the longest-lived dynasty in Chinese history, lasting for more than 800 years, and the first half of the period was called the Western Zhou. The Zhou Dynasty built the country into a pyramid, formulated a system of etiquette, and established rules for people on each floor of the pyramid.

The period after the Zhou Dynasty moved its capital to Luoyang was called the Eastern Zhou Dynasty, and the Eastern Zhou Dynasty was divided into two sections, the first half of which was called Spring and Autumn. Throughout the Spring and Autumn Period, big countries ate small countries, and eventually five people became overlords one after another, namely the Duke of Qi Huan, the Duke of Wen of Jin, the King of Chuzhuang, the King of Wu and the King of Yue, Goujian, they were known as the Five Hegemons of the Spring and Autumn Period.