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A．IL-1 B．IL-2C．IL-3 D．EPOE．IFN-α 刺激多能干细胞增生分化的是（）
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An airplane flies because its wings push down on the air flowing past them, and in reaction, the air pushes up on the wings. When an airplane is level or rising, the front edges of its wings ride higher than the rear edges. The angle the wings make with the horizontal is called the angle of attack. As the wings move through the air, this angle causes them to push air flowing under them downward. A sleeper angle of attack will cause the wings to push more air downward. The third law of motion voiced by English physicist Isaac Newton states that every action produces an equal and opposite reaction. In this case, the wings pushing air downward is the action, and the air pushing the wings upward is the reaction. This causes lift, the upward force on the plane, Lift is often explained using Bernoulli’s principle, which states that, in some circumstances, a faster moving fluid(流体) (such as air)will have a lower pressure than a slower moving fluid. The air on the top of an airplane wing is at a lower pressure than the air underneath the wing, but this is an effect of lift, not its cause.Lift is one of the four primary forces acting upon an airplane. The others are weight, thrust, and drag. Weight is the force that offsets lilt. because it acts in the opposite direction. The weight of the airplane must be overcome by the lift produced by the wings, if an airplane weighs 4.5 metric tons, then the lift produced by its wings must be greater than 4.5 metric tons in order for the airplane to leave the ground. Designing a wing that is powerful enough to lift an airplane off the ground, and yet efficient enough to fly at high speeds over extremely long distances, is one of the marvels of aircraft technology. What is the cause of "Lift"
On July 12, 1993, a young professor of American history named Frederick Jackson Turner stood up to speak. The scene was the American History Congress at the Chicago World’s Fair. (62) His paper was titled "The significance of the Frontier in American History." Turner had a new idea. (63) And many historians who heard him recognized that he had come upon a simple theory that seemed right.To Turner, the frontier was one of the most powerful forces shaping the American character. He pointed out that the frontier was a place for new beginnings, a place where men and women could build new lives. Thus, the frontier represented hope and opportunity to Americans. Turner also pointed out that these new lives on the frontier were shaped by tile hardships of surviving in the wilderness. Thus, life on the frontier produced determination in Americans and made them believe in the value of work. (64)According to Turner’s theory, the frontier was a place where everyone had to struggle equally hard. (65) Thus, frontier life helped shape the American ideal of equality, independence, and democracy. On July 12, 1993, a young professor of American history named Frederick Jackson Turner stood up to speak.
背景：某监理单位受业主委托，承担了某工程项目施工阶段监理工作。该工程项目的基础采用钢筋混凝土条形基础，主体为现浇钢筋混凝土框架结构。 事件1：在施工准备阶段进行施工组织设计审查时，总监理工程师发现部分内容不合格，需要承包单位修改，将施工组织设计退回承包单位并口头指出修改意见。承包单位修改完成后，再次交给监理单位审定，总监理工程师出于对承包单位的信任，没有重新审定，直接报送建设单位。 事件2：工程项目开工前，总监主持召开了第一次工地会议，并在会上介绍以下内容。(1)施工准备情况；(2)现场监理组织、人员及分工；(3)监理规划的主要内容。 【问题】
[听力原文]11-15Venice is a fascinating city between sea and sky. It is built on 117 islands. There aren’t any cars and buses, But it has 150 canals and 400 bridges. The narrow streets, with their historic names, are paved with stones but have no footpaths. They are lined with flower, shops and lights side by side. The squares are charming, The brick bridges are built high to; allow boats to pass tinder them.Every year thousands of tourists front the five continents visit this city. They are always amazed at the charm of her water and beautiful lights, which can make them free from all dust and cooled by the sea breezes.But because the level of the surrounding waters is constantly rising, the Venice faces a threat to its Very existence. And the Venetian love their city and want to stay there to save the Venice from the sea, Now various methods hove already been taken and a plan to protect the city is under investigation. How many islands are there in Venice（）
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