
A girl holds a book on the book fair in Porto, the second largest city of Portugal, on Sept. 1, 2017. The 17-day book fair will end on Sept. 17.(Xinhua/Zhang Liyun)

A girl holds a book on the book fair in Porto, the second largest city of Portugal, on Sept. 1, 2017. The 17-day book fair will end on Sept. 17.(Xinhua/Zhang Liyun)