Input: Read this: In the years to follow, public revelations on the state of Charles and Diana's marriage continued. Even though support for republicanism in Britain seemed higher than at any time in living memory, republicanism was still a minority viewpoint, and the Queen herself had high approval ratings. Criticism was focused on the institution of the monarchy itself and the Queen's wider family rather than her own behaviour and actions. In consultation with her husband and the Prime Minister, John Major, as well as the Archbishop of Canterbury, George Carey, and her private secretary, Robert Fellowes, she wrote to Charles and Diana at the end of December 1995, saying that a divorce was desirable.
Question: What state of affairs produced revelations and problems for Elizabeth?

Output: Charles and Diana's marriage


Input: Read this: The late nineteenth century also brought the systematic study of color theory, and particularly the study of how complementary colors such as red and green reinforced each other when they were placed next to each other. These studies were avidly followed by artists such as Vincent van Gogh. Describing his painting, The Night Cafe, to his brother Theo in 1888, Van Gogh wrote: "I sought to express with red and green the terrible human passions. The hall is blood red and pale yellow, with a green billiard table in the center, and four lamps of lemon yellow, with rays of orange and green. Everywhere it is a battle and antithesis of the most different reds and greens."
Question: What did Theo van Gogh paint?

Output: unanswerable


Input: Read this: Interstate 10, which runs southeast to northwest through town, connects Tucson to Phoenix to the northwest on the way to its western terminus in Santa Monica, California, and to Las Cruces, New Mexico and El Paso, Texas toward its eastern terminus in Jacksonville, Florida. I-19 runs south from Tucson toward Nogales and the U.S.-Mexico border. I-19 is the only Interstate highway that uses "kilometer posts" instead of "mileposts", although the speed limits are marked in miles per hour instead of kilometers per hour.
Question: What border does I-19 come close to? 

Output: U.S.-Mexico border


Input: Read this: In the 7th century, the Frankish merchant Samo, who supported the Slavs fighting their Avar rulers, became the ruler of the first known Slav state in Central Europe, which, however, most probably did not outlive its founder and ruler. This provided the foundation for subsequent Slavic states to arise on the former territory of this realm with Carantania being the oldest of them. Very old also are the Principality of Nitra and the Moravian principality (see under Great Moravia). In this period, there existed central Slavic groups and states such as the Balaton Principality, but the subsequent expansion of the Magyars, as well as the Germanisation of Austria, separated the northern and southern Slavs. The First Bulgarian Empire was founded in 681, the Slavic language Old Bulgarian became the main and official of the empire in 864. Bulgaria was instrumental in the spread of Slavic literacy and Christianity to the rest of the Slavic world.
Question: When did Samo become the ruler of the first known Slav state?

Output:
the 7th century