节点电压法是以（）为未知量，根据基尔霍夫电流定律列出节点方程而解得A.元件两端电压

四个样本率比较，P≤α，结论应为（）

A.各总体率不等或不全相等

B.各总体率均不相等

C.各样本率均不相等

D.各样本率不等或不全相等

E.各总体率相等

阅读下面文言文，完成1——4题。

　　[甲]自三峡七百里中，两岸连山，略无阙处。重岩叠嶂，隐天蔽日。自非亭午夜分，不见曦月。   　

　　至于夏水襄陵，沿溯阻绝。或王命急宣，有时朝发白帝，暮至江陵，其间千二百里，虽乘奔御风，不以疾也。  

　　春冬之时，则素湍绿潭，回清倒影。绝（巘或巚）多生怪柏，悬泉瀑布，飞漱其间。清荣峻茂，良多趣味。   

　　每至晴初霜旦，林寒涧肃，常有高猿长啸，属引凄异，空谷传响，哀转久绝。故渔者歌曰：“巴东三峡巫峡长，猿鸣三声泪沾裳。”   

　　[乙]风烟俱净，天山共色。从流飘荡，任意东西。自富阳至桐庐，一百许里，奇山异水，天下独绝。水皆缥碧，千丈见底。游鱼细石，直视无碍。急湍甚箭，猛浪若奔。夹岸高山，皆生寒树，负势竞上，互相轩邈；争高直指，千百成峰。泉水激石，泠泠作响；好鸟相鸣，嘤嘤成韵。蝉则千转不穷，猿则百叫无绝。鸢飞戾天者，望峰息心；经纶世务者，窥欲忘反。横柯上蔽，在昼犹昏；疏条交映，有时见日。    

1、解释下面句中词。       

（1）沿溯阻绝。 沿：_______________                      

（2）良多趣味。 良：_______________                            

（3）任意东西。东西：_______________                 

（4）窥谷忘反。 反：_______________                             

2、翻译下列句子。      

（1）虽乘奔御风，不以疾也。  

___________________________________________________________                

（2）风烟俱净，天山共色。   

___________________________________________________________ 

3、下面分析有误的一项是（ ）。      

A、“游鱼细石，直视无碍。”通过“游鱼细石”写出水的清澈。       

B、“悬泉瀑布，飞漱其间。”运用对偶的修辞手法，句式整齐，富有韵律。      

C、“泉水激石，泠泠作响；好鸟相鸣，嘤嘤成韵。”运用拟声叠词，构成一幅音韵和谐的画面。      

D、“重岩叠嶂，隐天蔽日。自非亭午夜分，不见曦月。”侧面烘托了山的高耸。  

4、甲乙两段都描写了奇山异水，但思想感情有差异，请结合原文的语句说说两文不同的思想感情。

___________________________________________________________

To compete in today’s fast-paced competitive environment, organizations are increasingly allowing contractors, partners, visitors and guests to access their internal enterprise networks. These users may connect to the network through wired ports in conference rooms or offices, or via wireless access points. In allowing this open access for third parties, LANs become (71 ) Third parties can introduce risk in a variety of ways from connecting with an infected laptop to unauthorized access of network resources to (72) activity. For many organizations, however, the operational complexity and costs to ensure safe third party network access have been prohibitive. Fifty-two percent of surveyed CISOs state that they currently use a moat and castle’s security approach, and admit that defenses inside the perimeter are weak. Threats from internal users are also increasingly a cause for security concerns. Employees with malicious intent can launch (73) of service attacks or steal (74) information by snooping the network. As they access the corporate network, mobile and remote users inadvertently can infect the network with (75) and worms acquired from unprotected public networks. Hackers masquerading as internal users can take advantage of weak internal security to gain access to confidential information.

A．reserved

B．confidential

C．complete

D．mysterious

阅读理解。

     As the population of the planet increases, so does the number of homes, businesses, parking lots, schools,

airports and roadways. All these structures use electricity and need to be lighted. Humans demand these lights.

They want their homes more comfortable and they want their streets sage. The problem is that researchers are

finding that all the light is having a negative effect on humans and wildlife as well.

     Less than 10 years ago I drove to a thinly populated section of my town, lay down in the middle of the road

and watched an attracted meteor shower (流星雨). The area was short of homes, street lights and traffic. If I

did that today, I wouldn't be able to see the meteor shower as well, and I would surely be run over by a car.

     Nowadays scientists are finding light pollution can be almost as bad as carbon dioxide pollution. If you've

ever taken a flight at night, the view is beautiful, but you must remember that all the light you see is wasted

electricity. The crew of the space shuttles see an even bigger picture of how extensive the wasted electricity

is worldwide.

      Additionally, electricity needs to be generated, and the generation of electricity creates pollution by giving

off greenhouse gases. This affects the air we breathe and our quality of life.

     Scientists are also studying the effects of light pollution on wildlife. Thousands of birds die each year when

they crash into highly lighted buildings, as they become puzzled by the light. It has been long known that tiny

sea turtle hatchlings become lost and follow lights on the shore instead of heading towards the sea.

     Fortunately, light pollution is one of the easiest sources of pollution that can be corrected without a negative

effect. Following some guidelines and a little searching on Google can give you many ideas on how to reduce

your contribution to light pollution.

1. The author tells the story in the second paragraph mainly to _____.

A. remember the past beauty of the town.

B. stress the advantages of less pollution

C. show the great changes of the town

D. prove the bad effects of light pollution

2. In the passage the author advises people ______.

A. to try to reduce unnecessary light.

B. not to ignore the beauty around.

C. to set proper light for animals

D. not to destroy the animal's living conditions.

3. What can be inferred from the passage?

A. Light pollution is difficult to deal with.

B. Light pollution is a threat to some animals.

C. Light pollution has nothing to do with global warming

D. Astronauts can't see clearly in space due to light pollution.

4. What is most likely to be discussed in the paragraph which follows the last paragraph?

A. The author's contribution to light pollution

B. Other sources of light pollution

C. Ways of reducing light pollution

D. More bad effects of light pollution

电动机转速提不起来的原因是重绕时（）。

A.进入杂物

B.未烘干

C.匝数过多

D.匝数过少