Sophie Chen is a 14﹣year﹣old girl from Taiwan． When she was 6years old， she did something amazing．

She finished a 2，100﹣kilometer bike journey from Xi'an， the capital city of Shanxi， to Turpan， a city in Xinjiang， with her parents． It took them two and a half months． Sophie became the youngest child in the world to have biked along the Silk Road． Chinese novel Journey to the West inspired her to do so．

That is not all． Sophie wrote a book about the long journey with her father Jack Chen， a professional outdoor explorer． On April 26， the book's English version （版本） Biking the Silk Road： 6﹣year﹣old Sophie's Fantasy Tour came out in Beijing．

Now Sophie studies at Ta Hwa High School． She sees the journey as a special experience in her life． She became more hardworking and learned history and geography better because of it．

On the way， she met many friendly local people and saw amazing things． She even picked grapes! "The grapes in Xinjiang were so big and sweet． I have never seen grapes like them in Taiwan，" she said．

Still， it was not easy． "The biggest challenge was the bad weather and road conditions，" she said． She wrote in the book， "It was terribly hot in the Gobi Desert． I almost got sunstroke and could never have enough to drink．"

Sophie has biked in other countries， such as the United States and Turkey． This summer holiday， she plans to ride a bike from Greece to Portugal in Europe．

81． How long is Sophie's bike journey？　　

82． What was the biggest challenge on Sophie's journey？　　

83． The underlined word "sunstroke" probably means "　　" in Chinese．

84． Try to put the underlined sentence into Chinese．　　

85． Give a proper title to the passage．