牛头刨床的主参数是（）。A、最大刨削宽度 B、最大刨削长度 C、工作台宽度 D、工作 发布时间：2017-11-05 16:44 │ 来源：www.tikuol.com 题型：单项选择题 问题： 牛头刨床的主参数是（）。A、最大刨削宽度B、最大刨削长度C、工作台宽度D、工作台长度
题型：单项选择题 Passage Four What began with the invention of the telephone in 1876 has today become a global net of cables, satellites, transmitters, and receivers that enables half the population of the planet to exchange works, data, and images in seconds. It could take less than 25 years more to give the other half of the world’s people this same power. The unified global telecommunications system, which is called "the Meganet’, represents the greatest construction project ever undertaken. If present trends continue, by early in the 21st century the Meganet will link every computer terminal, fax machine, databank, and telephone instrument on earth. Unlike its anarchic (无政府主义的) cousin the Internet, which evolved from free interaction among interest groups of computer users, the Meganet of local telephone service, long-distance lines, communications satellites, and mobile relays has been planned, constructed, regulated and largely sponsored by governments and for-profit business interests. As new materials and technologies bring reliable voice and data links to formerly isolated or closed communities, political and economic power struggles grow. The Meganet breaks long-established patterns of social identity and responsibility. Where private individuals have uncensored access to global information sources, local standards of legality or decency become difficult even to set, let alone to enforce. Economic values may shift, too. Public utility companies have long supplied electric power over miles of high-tension lines, or pumped water through underground pipelines into thousands of homes. Now they are finding that their power-line rights-of-way and physical into-home connections let them compete with cable TV and phone companies to supply information services as well. Meganet impacts are often double-edged for finance and business, too. New York’s Wall Street district lost 20% of its work force—some 100 000 jobs—in less than a decade, as computers took over tasks once performed by clerks and banks did more of their business by phone transfers and automated teller machines.The word "uncensored" (Line 2, Para. 4) probably means ______ .A．unguardedB．uncheckedC．unidentifiedD．unwarranted’ 查看答案
题型：单项选择题 研究有机物一般经过以下几个基本步骤：分离、提纯→确定实验式→确定分子式→确定结构式，以下用于研究有机物的方法错误的是 [ ]A．燃烧法是研究确定有机物成分的常用方法B．根据质谱图可以确定某有机物的相对分子质量C．核磁共振氢谱通常用于分析有机物的相对分子质量 D．对有机物分子红外光谱图的研究有助于确定有机物分子中的官能团 查看答案
题型：单项选择题 脊麻时神经纤维被阻滞的顺序是：（）A．温觉、痛觉、触觉、运动、压力、血管舒缩神经B．血管舒缩神经、温觉、痛觉、触觉、运动、压力C．血管舒缩神经、痛觉、触觉、温觉、运动、压力D．血管舒缩神经、运动、温觉、痛觉、触觉、压力E．运动、血管舒缩神经、温觉、痛觉、触觉、压力 查看答案
题型：单项选择题 学校升旗仪式上，当升旗手缓缓向下拉绳子时，旗子就会徐徐上升．这是由于旗杆顶部有一个 _________ 滑轮，它能改变力的方向， _________ （选填“能”或“不能”）省力．在铡刀、钢丝钳、天平、钓鱼杆这些杠杆中，使用时属于费力杠杆的是 _________ ． 查看答案