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.
One example is below.
Q: 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.
A: How many books are there in the British Library?
Rationale: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.
Q: Article: YOU probably think you know about London's problems. The people are unfriendly, it's way too expensive, and the food is terrible - so why do so many tourists flock there? London was named the world's most popular city between July and September 2013. It _ other world-famous cities such as New York and Paris, welcoming 4.9 million visitors, according to the UK Office for National Statistics. Amazingly, this was an increase of almost 19.5 percent on 2012 - the year when the Olympics happened in summer. So can London's success be explained? Well, maybe. As the English writer Samuel Johnson once said, "when a man is tired of London, he is tired of life". London life is often crazy and expensive, but if you can think of something, you can probably do it there. Anywhere in the city, you can often look around a great museum such as the British Museum, watch a concert at a historic venue like the Royal Albert Hall, or dance the night away in a cool nightclub such as Fabric. And it's not just about culture - there are also world-famous sporting venues around the city. Many tourists like to watch soccer matches at stadiums such as Chelsea's Stamford Bridge, Arsenal's Emirates Stadium, or Tottenham's White Hart Lane. Tourists even came to watch British tennis player Andy Murray's famous victory at the Wimbledon tennis tournament in 2013. Yes, but what about the food? Well, even if you don't like British food - and if you've never had real fish and chips, or a summer pudding, then perhaps you should wait until you've tried them - there is plenty of great food from all over the world available in London's many restaurants. London, like many of its buildings, has a long history, but also never lacks a vibrant pulse . All over the city, history and modernity come together to make it an essential place for tourists to discover.
Answer: To analyze why London appeals to tourists.
A:
What is the author's main purpose in writing the article?