Here is a question about this article: In 1682, William Penn founded the city to serve as capital of the Pennsylvania Colony. Philadelphia played an instrumental role in the American Revolution as a meeting place for the Founding Fathers of the United States, who signed the Declaration of Independence in 1776 and the Constitution in 1787. Philadelphia was one of the nation's capitals in the Revolutionary War, and served as temporary U.S. capital while Washington, D.C., was under construction. In the 19th century, Philadelphia became a major industrial center and railroad hub that grew from an influx of European immigrants. It became a prime destination for African-Americans in the Great Migration and surpassed two million occupants by 1950.
What is the answer to this question: When did it reach 2 million occupants>
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So... 1950

Here is a question about this article: The first attempts to use standard-frequency single-phase AC were made in Hungary as far back as 1923, by the Hungarian Kalman Kando on the line between Budapest-Nyugati and Alag, using 16 kV at 50 Hz. The locomotives carried a four-pole rotating phase converter feeding a single traction motor of the polyphase induction type at 600 to 1,100 V. The number of poles on the 2,500 hp motor could be changed using slip rings to run at one of four synchronous speeds. The tests were a success so, from 1932 until the 1960s, trains on the Budapest-Hegyeshalom line (towards Vienna) regularly used the same system. A few decades after the Second World War, the 16 kV was changed to the Russian and later French 25 kV system.
What is the answer to this question: What frequency did the line of Hungarian rail system used in 1923?
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So... 16 kV at 50 Hz

Here is a question about this article: According to a tradition first reported by Sulcard in about 1080, a church was founded at the site (then known as Thorn Ey (Thorn Island)) in the 7th century, at the time of Mellitus, a Bishop of London. Construction of the present church began in 1245, on the orders of King Henry III.
What is the answer to this question: Who ordered the construction of the church?
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So...
King Henry III