Problem: Given the question: Extract the answer to the question from the following context. Question: What does Philadelphia attract? Context: The area's many universities and colleges make Philadelphia a top international study destination, as the city has evolved into an educational and economic hub. With a gross domestic product of $388 billion, Philadelphia ranks ninth among world cities and fourth in the nation. Philadelphia is the center of economic activity in Pennsylvania and is home to seven Fortune 1000 companies. The Philadelphia skyline is growing, with several nationally prominent skyscrapers. The city is known for its arts, culture, and history, attracting over 39 million domestic tourists in 2013. Philadelphia has more outdoor sculptures and murals than any other American city, and Fairmount Park is the largest landscaped urban park in the world. The 67 National Historic Landmarks in the city helped account for the $10 billion generated by tourism. Philadelphia is the birthplace of the United States Marine Corps, and is also the home of many U.S. firsts, including the first library (1731), first hospital (1751) and medical school (1765), first Capitol (1777), first stock exchange (1790), first zoo (1874), and first business school (1881). Philadelphia is the only World Heritage City in the United States.
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The answer is:
domestic tourists

Problem: Given the question: Extract the answer to the question from the following context. Question: In what position are helicopters sometimes in when they are shot at by RPGs? Context: Rocket-propelled grenades can beand often areused against hovering helicopters (e.g., by Somali militiamen during the Battle of Mogadishu (1993)). Firing an RPG at steep angles poses a danger to the user, because the backblast from firing reflects off the ground. In Somalia, militia members sometimes welded a steel plate in the exhaust end of an RPG's tube to deflect pressure away from the shooter when shooting up at US helicopters. RPGs are used in this role only when more effective weapons are not available.
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The answer is:
hovering

Problem: Given the question: Extract the answer to the question from the following context. Question: What must happen regarding both house of parliaments regarding assent? Context: If the Governor General of Canada is unable to give assent, it can be done by either the Deputy of the Governor General of Canadathe Chief Justice of Canadaor another justice of the Supreme Court of Canada. It is not actually necessary for the governor general to sign a bill passed by a legislature, the signature being merely an attestation. In each case, the parliament must be apprised of the granting of assent before the bill is considered to have become law. Two methods are available: the sovereign's representatives may grant assent in the presence of both houses of parliament; alternatively, each house may be notified separately, usually by the speaker of that house. However, though both houses must be notified on the same day, notice to the House of Commons while it is not in session may be given by way of publishing a special issue of the Journals of the House of Commons, whereas the Senate must be sitting and the governor general's letter read aloud by the speaker.
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The answer is:
both houses must be notified on the same day