问题
选择题
下列各式可以用平方差公式计算的是 [ ]
A．（m+n）﹣（m﹣n）
B．（2x+3）（3x﹣2）
C．（﹣4x﹣3）（4x﹣3）
D．（a2﹣2bc2）（a2+2b2c）
答案
答案：C
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下列各式可以用平方差公式计算的是 [ ]
A．（m+n）﹣（m﹣n）
B．（2x+3）（3x﹣2）
C．（﹣4x﹣3）（4x﹣3）
D．（a2﹣2bc2）（a2+2b2c）
答案：C
Thanks to a combination of young businessmen, large numbers of university students and revitalization (新生) efforts by the local and national governments, today’s Nanjing has an 36 of youthful exuberance (繁茂) that would have been 37 only a few decades ago. 38 , the city, a booming city of 6.5 million on the banks of the Yangtze River some 185 miles west of Shanghai, bears 39 resemblance to the former capital of China that suffered the worst cruelty and violence of World War II. 40 Nanjing has shown a remarkable capacity for reinvention during its 2,500-year history. And in recent years, the city has moved 41 its tragic past to become a vital engine of China’s economic growth, thanks 42 to its position in the middle of China’s prosperous eastern seaboard. Growth has also 43 thanks to improved ground transportation: A new bullet train linking Nanjing and Shanghai started service last year, 44 travel time between the cities from several hours to just 75 minutes, and a Beijing-Shanghai high-speed line is 45 to open later this year, with a stop in Nanjing. Within the city, two metro lines were built in the last few years; 15 more are planned to begin service by 2030. Signs of Nanjing’s 46 wealth and optimism can be seen everywhere. In the heart of the downtown Xinjiekou district, a bronze statue of Sun Yat-sen, 47 the father of modern China, looks 48 over a busy 49 area. There is perhaps no more 50 symbol of the city’s transformation than the Zifeng Tower, a 1,480-foot skyscraper that opened its doors last May. 51 offices, restaurants and an InterContinental hotel, the tower is the second-tallest building in China and billed as the seventh-tallest in the world. Underlying all this development is a large Chinese and 52 student population — there are several major universities, plus a branch of Johns Hopkins’s international studies school. In fact, art and music 53 in all sorts of places. On a larger 54 , local government officials and private investors are pushing the city as a rising center for contemporary art and architecture, hoping to attract 55 from the neon-bathed streets of its neighbor Shanghai.
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