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.
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.
Example solution: How many books are there in the British Library?
Example explanation: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

Problem: Article: IMAGINE if there was a device that could do everything for you - wake you up every morning, chat with you and type your e-mails. The piece of technology in question would be smart, able to tell you about the weather and where the nearest restaurants are. The good thing is you no longer need to wonder, because something like this already exists. And its name is Siri. Siri is a voice recognition application designed for Apple products and the concept has been around for almost a year. When Siri first came out it could only speak English, but now it has "learned" lots of new languages, including Chinese, Cantonese and Taiwanese, reported The Wall Street Journal. So, you can give it orders in your mother tongue. But how could a cell phone or a computer "hear" what you are saying and understand it? This is all because of voice recognition technology. When you speak, your voice creates vibrations in the air - a bit like waves in the water when you throw a rock into the lake. The microphone receives the vibrations and the computer changes them into digital data that is then divided into many parts. They are analyzed one by one to see what pronunciations each part stands for. The computer then puts these pronunciations together into possible words according to its built-in dictionary. But figuring out the words is far from enough; building words into meaningful sentences is the most difficult part. The computer has to compare what it hears to a large library of known phrases and sentences to determine what the user is saying. However, people don't always talk in the most standard way and sometimes make grammatical mistakes. This is why traditional voice recognition software always requires you to remember keywords and to speak in a certain way. Fortunately, Siri isn't like that. It's not just "voice recognition"; it's "natural language understanding (NLU)". You can ask it things like "Do I need an umbrella today?" and it will know that you are asking about the weather, according to ABC News. "The key thing is NLU - understanding what you mean and what you want," Neil Grant from Nuance, a software company in the US, told The Guardian. "Historically, you had to learn a huge long list of commands . As NLU progresses, you can say what you want in a way that's natural to you."
Answer: Figuring out meaningful sentences based on the words.
Solution: Which step is the most complicated in the process of voice recognition according to the article?