Do encyclopedias know everything?
Long before Wikipedia（维基百科）or Encyclopedia Britannica（大英百科全书）, there was Pliny the Elder. He was a first—century Roman researcher. His assistants read to him while he ate dinner and while he bathed. All he while, Pliny took notes. He even considered walking a waste of time. His assistants carried him around Rome in a chair while he read.
All of this was done in preparation for his Historia Naturalis. The book was published in A. D. 77. It is considered the oldest surviving （现存的）encyclopedia on earth. There are 2, 500 chapters. They cover everything from mice to Mars.
"No Roman author has completed such a project, "Pliny proudly declared. Unluckily, two years after having published the encyclopedia, he died in a natural disaster.
Accidents can hardly be avoided. However, they can be recorded. Editors（编辑）of encyclopedias, like Pliny, organize the knowledge of our world. Like a valuable gift, the books are passed down through the ages. They begin their lives as a tool and end them as a historical record.
Therefore, in my opinion, an encyclopedia is not just a record of what its editors know, it's also a record of what they don't know.
Pliny was wrong when he said there were seven planets, including the Sun and the Moon. He was wrong, too, when he said Africans were black from being burnt by the Sun. After all, Historia Naturalis is a book edited by a Roman thousands of years ago. It contained all of the things he truly knew at the time. Similarly, I believe both Wikipedia and Encyclopedia Britannica have some inaccurate（不准确的）information. Even the biggest encyclopedias only represent what their editors know.
"The task of editing an encyclopedia can never be completed, " said Roger Lewinter, an American researcher. Encyclopedias can't record all of human knowledge but just some of it. They are always waiting for someone—you, perhaps—to improve them.
