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: In the last couple of years, there has been a craze about timetraveling TV series in China.This year, it seems like the South Korean drama writers have fallen in a deep, neverending love with the timetravel trend. Rooftop Prince A prince from the Joseon era (18th century), Lee Gak is _ 300 years forward into the future in Seoul 2012 with his entourage when he tries to investigate the suspicious circumstances which surround the death of the woman he loves.In the present, he finds a young woman who looks exactly like his beloved crown princess. Queen Inhyun's Man The drama, set during the Joseon era, features the hero Kim Boongdo as he tries to restore the exiled Queen Inhyun.It is in this time period he is given the timetraveling power that transports him to the future world where he makes friends with an actress playing the role of Queen Inhyun for a drama in her time. Dr Jin Jin Hyuk is a genius neurosurgeon.Through a mysterious power, Jin finds himself transported back in time 150 years.He begins treating people there, but the lack of equipment and medical knowledge of the period forces him to seek new ways to aid the sick.Through this challenging process, Jin eventually becomes a genuine doctor. Operation Proposal Kang Baekho realizes that he falls in love with his best friend, Ham Yiseul, on the day of her wedding to another man.He travels back in time to various events of their lives hoping to change the outcome of their relationship.Will Kang be able to change the course of their future?
Answer: They all feature timetravel.
Student:
What do the three TV series have in common?