机床导轨的作用是什么？对导轨有哪些基本要求？

社区矫正对象刘某因故意伤害罪被判缓刑两年。他从小娇生惯养，事事以自我为中心，逐渐造成行为偏执、冲动。矫正初期，无论社会工作者怎样努力，刘某总是沉默不语，消极抵触。但社会工作者坚持真心实意地关心刘某，逐渐使刘某开始对社会工作者敞开了心胸。本案例中，社会工作者坚守了（）的社会工作价值理念。

A.接纳

B.保密

C.个别化

D.可塑性

阅读理解。

     For more than twenty years scientists have been searching for signs of life on other planets. Most of

these searches have been done over the radio. The hope is that someone in outer space may be trying to

get in touch with us. Scientists also have sent radio and television messages on spaceships traveling

through space, on the chance that someone may be receptive (善于接受的) to such messages.

     Scientists are using powerful radio telescope to listen to signals from about 1,000 stars, all within 100

light years of earth. In addition, they will scan (扫视) the entire sky to "listen" for radio messages from

more distant stars. Using a computer, they will be able to monitor more than eight channels at one time.

Scientists are looking for any signal that stands out from the background noise.

     Of the 200 billion stars in the Milky Way galaxy (银河星系), scientists find that five percent are like

our sun. Perhaps half of them have a planet like earth. Such a planet would be a reasonable distance from

the star for temperatures to be right for the evolution of life. Based on the inhabitable (that can be lived in) planets in our galaxy, most scientists agree that chances are likely that one or more of these planets

support some life.

     However, many scientists wonder whether intelligent (有智力的) life exists on other planets. Some

believe that twenty years of searching without any intelligible (可理解的) messages shows that no one is

out there. They say that the evolution of intelligence comparable to ours is unlikely.

     Other scientists believe that our search hasn't been long enough to rule out the possibility that intelligent

life exists in our galaxy. Although our sun family in only about five billion years old, our galaxy is about 20

billions years old. In that time, some scientists think it is likely that civilizations are much more advanced

than ours. Perhaps these civilizations (文明) send us no signals; perhaps we have not recognized the

signals they have sent us. If we hope to find intelligent life, these scientists believe that we have to keep

looking.

1. According to the passage, how many planets in our galaxy might be inhabitable?

A. 5 billion

B. 10 billion

C. 15 billion

D. 200 billion

2. The first paragraph in this passage is mainly about ______.

A. how scientists are looking for signs of life on other planets

B. why scientists are looking for signs of life on other planets

C. where scientists are looking for signs of life on other planets

D. when scientists are looking for signs of life on other planets

3. The underlined word "monitor" in the passage means "______".

A. find

B. follow

C. check

D. form

4. Which of the statements is TRUE based on the information in the passage?

A. The earth is one of the oldest planets in our galaxy.

B. Most scientists believe that there is intelligent life on other planet.

C. Scientists are trying different ways to find signs of life on other planet.

D. Scientists don't believe that there might be life on other planets.

某机电工程公司施工总承包了一项大型原油储备库工程，该工程主要包括4台50000m3浮顶原油储罐及其配套系统和设施。工程公司项目部对50000m3浮顶储罐的施工方案进行了策划，确定罐壁焊缝采用自动焊的主体施工方案，为了减少脚手架的搭设和投入， 选用了适宜的内挂脚手架正装法组装管壁，确定主体施工方案后项目部编制了施工组织设计，并按规定程序进行了审批。 施工过程中，发生了如下事件 事件一：由于管壁自动焊接设备不能按计划日期到达施工现场，为不影响工程进度，项目部决定将罐臂焊缝自动焊改为焊条电弧焊（手工焊）。为此，项目部根据电弧焊方法修改了施工组织设计，由项目总工程师批准后实施，在施工过程中专业监理工程师发现，认为改变罐壁焊接方法属于重大施工方案修改，项目部的施工组织变更的审批手续不符合要求，因此报请总监理工程师下达了工程停工指令。 事件2：修改罐壁焊接方法后，工程公司项目部把焊缝的焊条电弧焊焊接质量控制的重点，制定了合理的焊接顺序和工艺要求，并制定了质量预控方案。 事件3：在对第一台焊接的50000m3浮顶进行罐壁焊缝射线检测及缺陷分析中，认为气孔和密集气孔是出现频次最多的超标缺陷，是影响焊接质量的主要因素，项目部采用因果分析图方法，找出了焊缝产生气孔的主要原因，制定了对后续的焊接施工中，项目部落实了对策表内容，提高了焊接质量。

事件三中，保证焊缝质量对策表应包括哪些内容？

为什么在GSM900系统中双工间隔：45MHz？

通常一个学科数据库包括哪些内容？建立学科数据库的现实意义又是什么？