Problem: Frederic Chopin:

All of Chopin's compositions include the piano. Most are for solo piano, though he also wrote two piano concertos, a few chamber pieces, and some songs to Polish lyrics. His keyboard style is highly individual and often technically demanding; his own performances were noted for their nuance and sensitivity. Chopin invented the concept of instrumental ballade. His major piano works also include mazurkas, waltzes, nocturnes, polonaises, etudes, impromptus, scherzos, preludes and sonatas, some published only after his death. Influences on his compositional style include Polish folk music, the classical tradition of J. S. Bach, Mozart and Schubert, the music of all of whom he admired, as well as the Paris salons where he was a frequent guest. His innovations in style, musical form, and harmony, and his association of music with nationalism, were influential throughout and after the late Romantic period.

Chopin wrote some music to lyrics, what language were the lyrics?
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A: Polish

Problem: Because of their long life, fast switching times, and their ability to be seen in broad daylight due to their high output and focus, LEDs have been used in brake lights for cars' high-mounted brake lights, trucks, and buses, and in turn signals for some time, but many vehicles now use LEDs for their rear light clusters. The use in brakes improves safety, due to a great reduction in the time needed to light fully, or faster rise time, up to 0.5 second faster[citation needed] than an incandescent bulb. This gives drivers behind more time to react. In a dual intensity circuit (rear markers and brakes) if the LEDs are not pulsed at a fast enough frequency, they can create a phantom array, where ghost images of the LED will appear if the eyes quickly scan across the array. White LED headlamps are starting to be used. Using LEDs has styling advantages because LEDs can form much thinner lights than incandescent lamps with parabolic reflectors.
Because of their high output, LED lights are very useful where?
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Answer: brake lights for cars

Q: What is a question about this article? If the question is unanswerable, say "unanswerable".
In the year 712, Muhammad bin Qasim, an Umayyad general, sailed from the Persian Gulf into Sindh in Pakistan and conquered both the Sindh and the Punjab regions along the Indus river. The conquest of Sindh and Punjab, in modern-day Pakistan, although costly, were major gains for the Umayyad Caliphate. However, further gains were halted by Hindu kingdoms in India in the battle of Rajasthan. The Arabs tried to invade India but they were defeated by the north Indian king Nagabhata of the Pratihara Dynasty and by the south Indian Emperor Vikramaditya II of the Chalukya dynasty in the early 8th century. After this the Arab chroniclers admit that the Caliph Mahdi "gave up the project of conquering any part of India."
Along with the Punjab, what did Muhammad bin Wasim conquer?
A: Sindh

Context and question: The final has never been contested by two teams from outside the top division and there have only been eight winners who weren't in the top flight: Notts County (1894); Tottenham Hotspur (1901); Wolverhampton Wanderers (1908); Barnsley (1912); West Bromwich Albion (1931); Sunderland (1973), Southampton (1976) and West Ham United (1980). With the exception of Tottenham, these clubs were all playing in the second tier (the old Second Division) - Tottenham were playing in the Southern League and were only elected to the Football League in 1908, meaning they are the only non-league winners of the FA Cup. Other than Tottenham's victory, only 24 finalists have come from outside English football's top tier, with a record of 7 wins and 17 runners-up: and none at all from the third tier or lower, Southampton (1902) being the last finalist from outside the top two tiers.
What team has never won the final?
Answer: unanswerable

Question: Many historical sites exist throughout the city, including 59 properties listed on the National Register of Historic Places. Of these, nine are among the 60 U.S. National Historic Landmarks in Connecticut. The New Haven Green, one of the National Historic Landmarks, was formed in 1638, and is home to three 19th-century churches. Below one of the churches (referred to as the Center Church on-the-Green) lies a 17th-century crypt, which is open to visitors. Some of the more famous burials include the first wife of Benedict Arnold and the aunt and grandmother of President Rutherford B. Hayes; Hayes visited the crypt while President in 1880. The Old Campus of Yale University is located next to the Green, and includes Connecticut Hall, Yale's oldest building and a National Historic Landmark. The Hillhouse Avenue area, which is listed on the National Register of Historic Places and is also a part of Yale's campus, has been called a walkable museum, due to its 19th-century mansions and street scape; Charles Dickens is said to have called Hillhouse Avenue "the most beautiful street in America" when visiting the city in 1868.
Is there an answer to this question: According to the National Register of Historic Places how many historical sites are there in New Haven?

Answer: 59

QUES: Greece's rail network is estimated to be at 2,548 km. Rail transport in Greece is operated by TrainOSE, a subsidiary of the Hellenic Railways Organization (OSE). Most of the country's network is standard gauge (1,565 km), while the country also has 983 km of narrow gauge. A total of 764 km of rail are electrified. Greece has rail connections with Bulgaria, the Republic of Macedonia and Turkey. A total of three suburban railway systems (Proastiakos) are in operation (in Athens, Thessaloniki and Patras), while one metro system is operational in Athens with another under construction.

Who is TrainOSE an owner of?
What is the answer?
ANS:
unanswerable