Books published by People's Education Publishing House are easier. Most parts of the country use PEP textbooks, and some places also use other versions of textbooks. The language is unified throughout the country, and other versions are used in mathematics, English, geography and physics! Take Xi 'an, Shaanxi as an example: our mathematics is published by Beijing Normal University, English by Shanghai Education, geography by Hunan Education and physics by Su Ke. Generally speaking, it is more difficult than the people's education version!