In this task, you will be presented with a context passage, a question about that paragraph, and a possible answer to that question. The task is to check the validity of the answer. Answer with "Yes" or "No".

[EX Q]: American Airlines Flight 11: FAA Awareness. Although the Boston Center air traffic controller realized at an early stage that there was something wrong with American 11, he did not immediately interpret the plane's failure to respond as a sign that it had been hijacked. At 8:14, when the flight failed to heed his instruction to climb to 35,000 feet, the controller repeatedly tried to raise the flight. He reached out to the pilot on the emergency frequency. Though there was no response, he kept trying to contact the aircraft. At 8:21, American 11 turned off its transponder, immediately degrading the information available about the aircraft. The controller told his supervisor that he thought something was seriously wrong with the plane, although neither suspected a hijacking. The supervisor instructed the controller to follow standard procedures for handling a "no radio" aircraft. The controller checked to see if American Airlines could establish communication with American 11. He became even more concerned as its route changed, moving into another sector's airspace. Controllers immediately began to move aircraft out of its path, and asked other aircraft in the vicinity to look for American 11. At 8:24:38, the following transmission came from American 11: American 11: We have some planes. Just stay quiet, and you'll be okay. We are returning to the airport. The controller only heard something unintelligible; he did not hear the specific words "we have some planes." The next transmission came seconds later: American 11: Nobody move. Everything will be okay. If you try to make any moves, you'll endanger yourself and the airplane. <sep>What were the first things done by America 11 that led the air traffic controller to notify his supervisor that something was wrong with the flight?<sep>There was no response
[EX A]: No

[EX Q]: In the popular mind, the history of Hong Kong, long the entryway to China for Westerners, begins in 1841 with the British occupation of the territory. However, it would be wrong to dismiss the long history of the region itself. Archaeologists today are working to uncover Hong Kong's past, which stretches back thousands of years. You can get a glimpse into that past at Lei Cheng Uk Museum's 1,600-year-old burial vault on the mainland just north of Kowloon. In 1992, when construction of the airport on Chek Lap Kok was begun, a 2,000-year-old village, Pak Mong, was discovered, complete with artifacts that indicated a sophisticated rural society. An even older Stone Age site was discovered on Lamma Island in 1996. While Hong Kong remained a relative backwater in early days, nearby Guangzhou (Canton) was developing into a great trading city with connections in India and the Middle East. By a.d. 900, the Hong Kong islands had become a lair for pirates preying on the shipping in the Pearl River Delta and causing a major headache for burgeoning Guangzhou; small bands of pirates were still operating into the early years of the 20th century. In the meantime, the mainland area was being settled by incomers, the "Five Great Clans": Tang, Hau, Pang, Liu, and Man. First to arrive was the Tang clan, which established a number of walled villages in the New Territories that still exist today. You can visit Kat Hing Wai and Lo Wai, villages with their walls still intact. Adjacent to Lo Wai is the Tang Chung Ling Ancestral Hall, built in the 16th century, which is still the center of clan activities. The first Europeans to arrive in the Pearl River Delta were the Portuguese, who settled in Macau in 1557 and for several centuries had a monopoly on trade between Asia, Europe, and South America. As Macau developed into the greatest port in the East, it also became a base for Jesuit missionaries; it was later a haven for persecuted Japanese Christians. While Christianity was not a great success in China, it made local headway, evidenced today by the numerous Catholic churches in Macau's historic center. Intermarriage with the local Chinese created a community of Macanese, whose culture can still be seen in Macau's architecture and cuisine. <sep>Why did traders from Canton have problems in the Pearl River Delta?<sep>Because the water was too shallow
[EX A]: No

[EX Q]: According to the radar reconstruction, American 77 reemerged as a primary target on Indianapolis Center radar scopes at 9:05, east of its last known position. The target remained in Indianapolis Center's airspace for another six minutes, then crossed into the western portion of Washington Center's airspace at 9:10. As Indianapolis Center continued searching for the aircraft, two managers and the controller responsible for American 77 looked to the west and southwest along the flight's projected path, not east-where the aircraft was now heading. Managers did not instruct other controllers at Indianapolis Center to turn on their primary radar coverage to join in the search for American 77. In sum, Indianapolis Center never saw Flight 77 turn around. By the time it reappeared in primary radar coverage, controllers had either stopped looking for the aircraft because they thought it had crashed or were looking toward the west. Although the Command Center learned Flight 77 was missing, neither it nor FAA headquarters issued an all points bulletin to surrounding centers to search for primary radar targets. American 77 traveled undetected for 36 minutes on a course heading due east for Washington, D.C. By 9:25, FAA's Herndon Command Center and FAA headquarters knew two aircraft had crashed into the World Trade Center. They knew American 77 was lost. At least some FAA officials in Boston Center and the New England Region knew that a hijacker on board American 11 had said "we have some planes." Concerns over the safety of other aircraft began to mount. A manager at the Herndon Command Center asked FAA headquarters if they wanted to order a "nationwide ground stop." While this was being discussed by executives at FAA headquarters, the Command Center ordered one at 9:25. The Command Center kept looking for American 77. At 9:21, it advised the Dulles terminal control facility, and Dulles urged its controllers to look for primary targets. At 9:32, they found one. Several of the Dulles controllers "observed a primary radar target tracking eastbound at a high rate of speed" and notified Reagan National Airport. FAA personnel at both Reagan National and Dulles airports notified the Secret Service. <sep>At which times did all this take place<sep>8:45
[EX A]:
No

