In this task, you're given an article and an answer. Your task is to generate the question for the answer based on the given article.

Let me give you an example: Article: There are a lot of public libraries in Britain. These libraries have more than one hundred and fifteen million books, not including those libraries of public schools. Public libraries not only lend books, music records but also help children, patients in hospitals and others to get special play readings, film shows and so on. The first public libraries were founded in about the year 1850. Today's public libraries usually have a reading-room, a lending room and a reference room. The greatest and most famous library in Britain is that of the British Library in London. It was founded in 1973 and has over 10, 000, 000 books. It has nearly every magazine, newspaper and book published in Britain and other parts across the world.
Answer: 10,000,000 or less.
The answer to this example can be: How many books are there in the British Library?
Here is why: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

OK. solve this:
Article: Joseph Francis Charles Rock (1884-1962) was an Austrian-American explorer, botanist, and anthropologist . For more than 25 years, he travelled extensively through Tibet and Yunnan, Gansu, and Sichuan provinces in China before finally leaving in 1949. In 1924, Harvard sent Joseph Francis Rock on a treasure hunt through China's southwestern provinces--the Wild West of their day. But gold and silver weren't his task: Rock, a distinguished botanist, sought only to fill his bags with all the seeds, saplings, and shrubs he could find. During his three-year expedition, he collected 20,000 specimens for the Arnold Arboretum . Botany, though, was just one of Rock's strengths. As an ethnologist , he took hundreds of photographs of the Naxi, a tribe in Yunnan province, recording their now-lost way of life for both Harvard and National Geographic, and took notes for an eventual 500-page dictionary of their language. His hand-drawn map of his travels through China's "Cho-Ni" territory, in the Harvard Map Collection, includes more than a thousand rivers, towns, and mountains indicated in both English and Chinese, and was so well made that the U.S. government used it to plan aerial missions in World War II. Scientist, linguist, cartographer, photographer, writer--Rock was not a wallflower in any sense. Arrogant and self-possessed, he would walk into a village or warlord's place "as if he owned the place," said Lisa Pearson, the Arboretum's head librarian. In declaring his successful return under the headline "Seeking Strange Flowers, in the Far Reaches of the World," the Boston Evening Transcript ran a large photo of the daring explorer wearing in a woolly coat and fox-skin hat. "In discussing his heroism including hair-raising escapes from death either from mountain slides, snow slides and robber armies, he waves the idea away as if it is of no importance." The Arboretum and Rock parted ways after 1927, mainly because his trip cost Harvard a fortune--about $900,000 in today's dollars. Fortunately, many of his specimens, many of his amazing photos, and his great stories remain.
Answer: Rock's exploration in Southwest China.
Answer:
What is the passage mainly about?