按照[SiO4]4-的连接方式,石英有三种存在状态,870℃以下稳定存在的是()A、

题型:单项选择题

问题:

按照[SiO4]4-的连接方式,石英有三种存在状态,870℃以下稳定存在的是()

A、方石英

B、单斜石英

C、石英

D、鳞石英

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题型:单项选择题

阅读理解。

     We are all busy talking about and using the Internet, but how many of us know the history of the

 Internet?

     Many people are surprised when they find that the Internet was set up in the 1960s. At that time ,

 computers were large and expensive. Computer networks (网络) didn't work well. If one computer in the

  networks broke down, then the whole network stopped. So a new network system (系统) had to be set

  up. It should be good enough to be used by many different computers. If part of the network was not

 working, information (信息) could be sent through another part. In this way computer network system

 would keep on working all the time.

     At first, the Internet was only used by the goverment (政府),but in the early 1970s, university (大学),

 hospitals and banks were allowed to use it too. Howerver,computers were still expensive and the Internet

  was difficult to become cheaper and easier to use. Scientists had also developed software (软件) that

 made "Surfing" (浏览) the Internet more convenient (方便).

     Today it is easy to get-on-line and it is said that millions of people use the internet every day. Sending

  e-mail is more and more popular among students.

     The Internet has now become one of the most important parts of people's life.

1. The Internet has a history of _____ years.

    A. about 40

    B. less than 30

     C. more than 45

    D. nearly 35

2. Scientists set up a new network system to _____ .

    A. make the computer cheaper.

    B. use the computer widely

    C. make the computer go well

    D. develop new softwares

3. The Internet was widely used in the _____ .

    A. 1960s

    B. 1970s

    C. 1980s

    D. 1990s

4. The underlined words "get-on-line" in Chinese means "_____ "

    A. 上机

    B. 上网

    C. 接线

    D. 买电脑

5. Which of the following is NOT ture?

    A. In the 1960s computer networks system went wrong easily.

    B. Computers are much cheaper than before.

    C. Today the Internet is used everywhere.

    D. People had enough softwares to get on-line fifteen years ago

题型:单项选择题

试分析高渗性脱水早期机体的代偿反应及发生机制。

题型:单项选择题

患者,女,30岁,停经50天, * * 有少许出血3天,无腰酸腹痛,小便频数,舌淡苔白,脉沉滑尺弱,尿妊娠试验阳性,治疗代表方剂是

A.寿胎丸
B.肾气丸
C.圣愈汤
D.胎元饮
E.补肾固冲汤

题型:单项选择题

零售业务的店面内只许存放民用小包装的危险化学品,其存放总质量不得超过( )

A.1

B.2

C.3

D.4

题型:单项选择题

塑壳式自动空气断路器,可以用于保护()的用电设备。

A.容量不大

B.总开关

C.容量大的分路开关

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