Teacher: 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.
Teacher: Now, understand the problem? If you are still confused, see the following 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.
Solution: How many books are there in the British Library?
Reason: In the Article, 10,000,000 is mentioned for the number of books available in the British Library, so this is a good question.

Now, solve this instance: Article: Hubert Joseph Schlafly was an electrical engineer who helped change the way actors, politicians and other people speak on television. In 1950, he and two other men developed the teleprompter. One co-worker, Fred Barton, was an actor. He had an idea for a tool that would help television actors read their lines without having to memorize them. The other co-worker was Irving Kahn. He worked as vice-president of radio and television at 20thCentury Fox. The first teleprompter involved a person who held a long piece of paper printed with big letters. As the actor read the lines, another person would move the paper ahead on the device . The teleprompter was first used on a television program called "The First Hundred Years." Later versions used television screens to show the words that were to be read. Hub Schlafly and his co-workers believed that many companies would want to buy the teleprompter. So, they left their jobs and created the TelePrompTer Corporation to sell their invention. In 1952, former President Herbert Hoover became the first politician to use a teleprompter. The former president was speaking at the Republican National Convention in Chicago, USA. For a brief time, he stopped reading and began to talk about a subject not written in his speech. When Hoover wanted to continue the speech, the words on the teleprompter were not moving. He then said the machine should be restarted and viewers became aware of the new invention. Many reporters wrote about that incident, creating a new level of publicity for the teleprompter. Soon more and more politicians started to use it to face the television camera while reading prepared statements, instead of looking down at their notes. Then the device was used for almost all live television broadcasts.
Answer: The history of a useful electrical device.
Student:
What is the text mainly about?