A mother and daughter read books during a book fair in Nanning, capital of South China’s Guangxi Zhuang autonomous region, April 21, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]

Children and adults read books during a book fair in Nanning, capital of South China’s Guangxi Zhuang autonomous region, April 21, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]

A mother and son read a book during the reading activity held by a kindergarten in Qingdao city, East China’s Shandong province, April 22, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]

A father takes his baby to read a book at a library in Yuqing county, Southwest China’s Guizhou province, April 22, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]

Children and adults read books during a reading activity in Anqing city, East China’s Anhui province, April 22, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]

Children and adults select books during a reading activity held by Children’s Library in Nantong city, East China’s Jiangsu province, April 22, 2018. April 23 marks the World Book Day, which was promoted by UNESCO as a worldwide celebration of reading since 1995. [Photo/Xinhua]