在美国人心目中最伟大的总统调查中，1948、1962、1977、1982年四次评

马栾哥尼效应

理论证明，取离星球中心无穷远处为引力势能的零势点时，以物体在距离星球中心为r处的引力势能可表示为：E_p=-G

Mm

r

．G为万有引力常数，M、m表示星球与物体的质量，而万有引力做的功则为引力势能的减少．已知月球质量为M、半径为R，探月飞船的总质量为m．月球表面的重力加速度为g，万有引力常数G．

（1）求飞船在距月球表面H（H＞

R

3

）高的环月轨道运行时的速度v；

（2）设将飞船从月球表面发送到上述环月轨道的能量至少为E．有同学提出了一种计算此能量E的方法：根据E=

1

2

mv2+mgH，将（1）中的v代入即可．请判断此方法是否正确，并说明理由．如不正确，请给出正确的解法与结果（不计飞船质量的变化及其他天体的引力和月球的自转）．

嚼槟榔引起的口腔癌最好发于（）。

A．唇

B．牙龈

C．口底

D．颊部

E．舌

Cultural responses to modernization often manifest themselves in the mass media. For example, Aldous Huxley, in Brave New World, created a fictional world in which he cautioned readers that modern science and technology posed a threat to individual dignity. Charlie Chaplin’s film Modern Times, set in a futuristic manufacturing plant, also told the story of the dehumanizing impact of modernization and machinery. Writers and artists, in their criticisms of the modern world, often point to technology’s ability to alienate people from one another, capitalism’s tendency to foster greed, and government’s inclination to create bureaucracies that oppress rather than help people.

Among the major values of the modern period, four typically manifest themselves in the cultural environment: celebrating the individual, believing in rational order, working efficiently, and rejecting tradition. These values of the modern period were originally embodied in the printing press and later in newspapers and magazines. The print media encouraged the vision of individual writers, publishers, and readers who circulated new ideas. Whereas the premodern period was guided by p beliefs in a natural or divine order, becoming modern meant elevating individual self-expression to a central position. Along with democratic breakthroughs, however, individualism and the Industrial Revolution triggered modern forms of hierarchy, in which certain individuals and groups achieved higher standing in the social order. For example, those who managed commercial enterprises gained more control over the economic ladder, while an intellectual class of modern experts, who mastered specialized realms of knowledge, gained increasing power over the nation’s social, political, and cultural agendas.

To be modern also meant to value the capacity of organized, scientific minds to solve problems efficiently. Progressive thinkers maintained that the printing press, the telegraph, and the railroad in combination with a scientific attitude would foster a new type of informed society. At the core of this society, the printed mass media, particularly newspapers, would educate the citizenry, helping to build and maintain an organized social framework. Journalists strove for the premodern ideal through a more fact-based and efficient approach to reporting. They discarded decorative writing and championed a lean look. Modern front-page news de-emphasized description, commentary, and historical context. The lead sentences that reported a presidential press conference began to look similar, whether they were on the front page in Tupelo, Mississippi, or Wahpeton, North Dakota. Just as modern architecture made many American skylines look alike, the front pages of newspapers began to resemble one another.

Finally, to be modern meant to throw off the rigid rules of the past, to break with tradition. Modern journalism became captivated by timely and immediate events. As a result, the more standardized forms of front-page journalism, on the one hand, championed facts and current events while efficiently meeting deadlines. But on the other hand, modern newspapers often failed to take a historical perspective or to analyze sufficiently the ideas underlying these events.

The author seems to suggest that（）

A. the mass media have created the modern culture

B. modern culture have revolutionized the mass media

C. technology has changed the role of the mass media

D. the mass media are often critical of the modern culture

用砂轮机磨（）时，压力不能太大，操作中必须经常将（）浸入冷水进行冷却，以保证加工后的（）不退火。