| Meteors are ephemeral. They will
usually vanish before you have a chance to point them out to somebody else. This
makes them suitable for starry-eyed lovers to wish upon, but modern technology
can put shooting stars to more profitable use. Next time you see one, bear in
mind that a dispatcher may be using it to help him marshal a fleet of
long-distance lorries. To human eyes, a meteor is beautiful. To a radio wave, it is just another thing to bounce off, and bouncing radio waves off the sky is not new. Left to themselves radio waves travel in straight lines, which limits their range. To get them round corners, and over the horizon, they need something to bounce off. In the ionosphere—the uppermost level of the atmosphere—the sun’s rays break down molecules into positively charged ions and free electrons. These can reflect (and refract) radiation. The A. (A) What’s the use of radio waves reflected from meteor trails B. (B) Why do people think meteors are mysterious C. (C) When was the first meteor discovered D. (D) How many countries have set up Meteor Communications systems [单项选择]不属于ATM技术特点的是（）．
A. 信元由53个字节组成 B. 结合电路交换和分组交换的优点 C. 包括数据链路层的功能 D. 简化了网络层的功能 [单选题]高温天气现场作业人员要随身携带( )，避免发生中暑事件。
A.白开水 B.防暑药物 C.盐汽水 D.人丹 [单选题]《变电评价管理规定》规定:精益化评价中发现的停电试验项目超周期设备，且最近1次年度评价为“注意状态”或“正常状态”，1年内开展停电检修，停电检修前应加强（ ）。
A.分析总结 B.及时追踪 C.状态跟踪 D.状态评价 [单选题]当离心泵油底壳润滑油变质后,其可能导致( )。
A.轴承温度变高 B.振动值增大 C.驱动电机电流增大 D.其他选项均有可能 [判断题]接地线应存放在固定地点。装、拆接地线应做好记录，交接班时应交待清楚。
A.正确 B.错误 [简答题]设备点检制的特点（6定）是指什么？
[单选题]机上发生的任何危险物品事件，客舱乘务员都应立即通知机长，机长需要了解所采取的一切行动和及其效果。
A.是 B.否 [多选题]运营分公司安全管理执行( )齐抓共管的原则,各级领导要把安全工作当作首要任务来抓,加强安全管理和安全思想教育,强化员工安全意识。
A.党 B.政 C.工 D.团 [单项选择]At the fall 2001 Social Science History Association convention in Chicago, the Crime and Justice network sponsored a forum on the history of gun ownership, gun use, and gun violence in the United States. Our purpose was to consider how social science history might contribute to the public debate over gun control and gun rights. To date, we have had little impact on that debate. It has been dominated by mainstream social scientists and historians, especially scholars such as Gary Kleck, John Lott, and Michael Bellesiles, whose work, despite profound flaws, is politically congenial to either opponents or proponents of gun control.① Kleck and Mark Gertz, for instance, argue on the basis of their widely cited survey that gun owners prevent numerous crimes each year in the Untied States by using firearms to defend themselves and their property. If their survey respondents are to be believed, American gun owners shot 100,000 criminals in 1994 in self-defense—a preposterous number.
A. Gun control should be tightened. B. Guns have little to do with murder. C. Gun culture was the result of high homicide rates in America. D. The statistics that earlier historians produced of gun ownership is reliable. [判断题]线圈通过电流会有感应电压产生。（）
A.正确 B.错误 [判断题]根据《旅客和机组携带危险品的航空运输规范》附录A，电动轮椅（防漏型电池驱动）可以做为航空托运行李运输。
A.正确 B.错误 [单项选择]下列关于实型变量书写正确的是
A. E3 B. 2e0.3 C. 1.2e3 D. 1.2E0.3 [单选题]根据《建筑施工安全管理规范》(DB33/1116-2015),货用施工升降机吊笼顶板应采用厚度不少于( )mm钢板封闭,防止上部物体穿透。
A.1.0 B.1.5 C.2.0 D.3.0 [简答题]液体在何种情形下产生静电？
[单选题]由于工程负责人不按规范指导施工，强令他人违章作业，或片面追求施工进度，导致施工质量标准降低而造成质量事故。则此事故属于（ ）。
A.操作责任事故 B.技术原因引发的质量事故 C.指导责任事故 D.社会、经济原因引发的质量事故 我来回答: 提交
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