题目

已知抛物线，过点P(4,0)的直线与抛物线相交于A(两点，则y的最小值是 答案：32 Qian Xuesen was born in Shanghai on December 11th, 1911. He is known as "the father of China's space program" and "the king of the rocket".When he was 24 years old, Qian went to America for further study. After graduation, he worked in America for a few years, where his working conditions were better. In the early 1950s, he heard New China had been founded and decided not to stay in America any longer. He succeeded in coming back to his motherland in 1955 though the American government tried to stop him.In 1956, Qian Xuesen suggested setting up a special organization, which later became the leading organization for China's rocket and air travel programs. In June 1964, China successfully created its first medium rocket. Qian also played an important role in developing China's first man-made satellite. On April 24, 1970, "Dongfanghong-1" was successfully sent into the air.In 1964, a young man wrote Qian Xuesen a letter and pointed out a mistake in his published article. Qian immediately answered the letter and encouraged the young man to write an article about the mistake.Zhu Yilin, who was said to be the last student of Qian Xuesen, once said, "I learned a lot of professional knowledge as well as the spirit and attitude that a scientist should have from Mr. Qian, especially his deep love for the motherland. Without that, he couldn't have helped to develop science and technology when new China was badly in need of scientists for its development. Without that, he would not have made the great contribution (贡献) to rocket industry in the late 1950s and nearly 1960s when conditions in China were too hard."Mr. Qian has been dead for eleven years, but he will live in the memory of Chinese people forever.1.Why did Qian Xuesen go to America when he was young?A.To find a new job. B.To receive further study.C.To meet with his parents. D.To find better working conditions.2.What is Paragraph 3 mainly about?A.The way Qian Xuesen tried to return to China. B.The reason why a special organization was set up.C.The contribution Qian Xuesen has made to China. D.The role Qian Xuesen played in making the satellite.3.In Zhu Yilin's opinion, what made Qian Xuesen work hard for his motherland?A.His love for the motherland. B.His working experience.C.His professional knowledge. D.His attitude towards science.