Problem: Please answer a question about the following article about United States Air Force:
The service's B-2A aircraft entered service in the 1990s, its B-1B aircraft in the 1980s and its current B-52H aircraft in the early 1960s. The B-52 Stratofortress airframe design is over 60 years old and the B-52H aircraft currently in the active inventory were all built between 1960 and 1962. The B-52H is scheduled to remain in service for another 30 years, which would keep the airframe in service for nearly 90 years, an unprecedented length of service for any aircraft. The B-21 is projected to replace the B-52 and parts of the B-1B force by the mid-2020s.
When did the B-2A aircraft enter into service of the US Air Force?
A: 1990s

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The decision to change strategy is sometimes claimed as a major mistake by the Oberkommando der Luftwaffe (OKL). It is argued that persisting with attacks on RAF airfields might have won air superiority for the Luftwaffe. Others argue that the Luftwaffe made little impression on Fighter Command in the last week of August and first week of September and that the shift in strategy was not decisive. It has also been argued that it was doubtful the Luftwaffe could have won air superiority before the "weather window" began to deteriorate in October. It was also possible, if RAF losses became severe, that they could pull out to the north, wait for the German invasion, then redeploy southward again. Other historians argue that the outcome of the air battle was irrelevant; the massive numerical superiority of British naval forces and the inherent weakness of the Kriegsmarine would have made the projected German invasion, Unternehmen Seelowe (Operation Sea Lion), a disaster with or without German air superiority.

What does OKL stand for?
Answer: Oberkommando der Luftwaffe

Problem: Estonia (i/stoni/; Estonian: Eesti [esti]), officially the Republic of Estonia (Estonian: Eesti Vabariik), is a country in the Baltic region of Northern Europe. It is bordered to the north by the Gulf of Finland, to the west by the Baltic Sea, to the south by Latvia (343 km), and to the east by Lake Peipus and Russia (338.6 km). Across the Baltic Sea lies Sweden in the west and Finland in the north. The territory of Estonia consists of a mainland and 2,222 islands and islets in the Baltic Sea, covering 45,339 km2 (17,505 sq mi) of land, and is influenced by a humid continental climate.
What is the official name for Estonia?
The answer is the following: the Republic of Estonia

"Superstorm Sandy" struck Atlantic City on October 29, 2012, causing flooding and power-outages but left minimal damage to any of the tourist areas including the Boardwalk and casino resorts, despite widespread belief that the city's boardwalk had been destroyed. The source of the misinformation was a widely circulated photograph of a damaged section of the Boardwalk that was slated for repairs, prior to the storm, and incorrect news reports at the time of the disaster. The storm produced an all-time record low barometric pressure reading of 943 mb (27.85") for not only Atlantic City, but the state of New Jersey.
Why was there a photo of the Boardwalk if it wasn't actually damaged in the storm?
the Boardwalk that was slated for repairs, prior to the storm

Input: Beyonce
Beyonce's vocal range spans four octaves. Jody Rosen highlights her tone and timbre as particularly distinctive, describing her voice as "one of the most compelling instruments in popular music". While another critic says she is a "Vocal acrobat, being able to sing long and complex melismas and vocal runs effortlessly, and in key. Her vocal abilities mean she is identified as the centerpiece of Destiny's Child. The Daily Mail calls Beyonce's voice "versatile", capable of exploring power ballads, soul, rock belting, operatic flourishes, and hip hop. Jon Pareles of The New York Times commented that her voice is "velvety yet tart, with an insistent flutter and reserves of soul belting". Rosen notes that the hip hop era highly influenced Beyonce's strange rhythmic vocal style, but also finds her quite traditionalist in her use of balladry, gospel and falsetto. Other critics praise her range and power, with Chris Richards of The Washington Post saying she was "capable of punctuating any beat with goose-bump-inducing whispers or full-bore diva-roars."

Why is Beyonce known as the centerpiece of Destiny's Child?
Output: Her vocal abilities

Problem: Please answer a question about the following article about Catalan language:
Despite its relative lexical unity, the two dialectal blocks of Catalan (Eastern and Western) show some differences in word choices. Any lexical divergence within any of the two groups can be explained as an archaism. Also, usually Central Catalan acts as an innovative element.
What are the two dialectical groups of Catalan?
A:
Eastern and Western