出口段包括出口活套塔、静电涂油机、表面质量观察台、针孔探测仪、边缘针孔探测仪、5号张

典型的交换式局域网是交换式以太网，它的核心部件是 ______。

如图所示是一列简谐横波在t=0时的波形图，介质中的质点P沿y轴方向做简谐运动的表达式为y=10sin5πt（cm），下列说法中正确的是（　　）

A．这列简谐波的周期为4.0s

B．这列简谐波的振幅为20cm

C．这列简谐波沿x轴负向传播

D．这列简谐波的传播速度为10m/s

Watch out, Yahoo. There is a search engine out there with super speed and accuracy. It’s very cool.

Google is the Web’s largest search engine. In just two years it has gained a reputation for surprising speed and accuracy, delivering what you are looking for in a second. The site now does this 40 million times a day --- a number achieved without spending a penny on a TV or newspaper ad.

Google doesn’t need them. In the past six months alone, the site has won a Webby (the online version of the Oscar) for technical excellence, set a new record for search engines by indexing a billion Web pages.

Yahoo still has ten times the audience, but Google consistently ranks first in customer satisfaction: 97% of users find what they are looking for most or all of the time. “You see people smile when they use it, like they’ve found something no one else knows about,” says Danny Sullivan, editor of an online newsletter.

No one is smiling more than Larry Page, 27, and Sergey Brin, 26, who seem certain to become billionaires when the company goes public, probably sometime in 2004. they make a great comedy duo(成对的表演者)。When they first met as Ph. D. students, the pair say, they found each other horrible – “I still find him horrible,” adds Brin – but driven together by a computer-science project aimed at coming up with better ways of searching the Web.

The idea behind the Google is that traditional search engines are stupid. They think relevance (关联) is based on repetition; if you type in a request for Tiger Woods, say, you’ll get websites listed according to how many times those words appear. Not only is this no guarantee of quality, but it’s also open to abuse. If you own a Tiger fan site and want to lead more people to it, simply type his name thousands of times in the site’s source code(编码).

1What does the underlined word “them” in the third paragraph refer to?

A. 40 million times              B. Speed and accuracy. 

C. TV and newspaper ads.        D. Web pages

2. Which of the following win greater customer satisfaction?

A. Yahoo        B. Tiger Woods      C. Larry Page     D. Google

3. It can be inferred that Page and Brin ______________.

A. hold very important positions in Google

B. are two ordinary computer programmers of Google.

C. used to hate each other very much

D. hold quite different opinions of computer-science

4. We can learn from the last paragraph that ___________.

A. Google is open to abuse

B. Google remains a traditional search engine

C. Google thinks relevance is based on repetition

D Google is better than traditional search engines

采用点柱固定绞车；绞车底座最短长度为（）

A、1.5m

B、1..6m

C、1.8m

D、2.0m

2009年度全国“农民工总量”为22978万人，比上年增加436万人。其中“外出农民工”14533万人，比上年增加492万人在外出农民工中，“住户中外出农民工”11567万人，比上年增加385万人；“举家外出农民工”2966万人，比上年增加107万人。
从输出地看，2009年东部地区农民工10017万人，同比增长3.1%，东部地区农民工占全国农民工总量的比重为43.6%；中部地区农民工7146万人．，同比增长0.9%，中部地区农民工占全国农民工总量的31.1%；西部地区农民工5815万人，同比增长1.2%，西部地区农民工占全国农民工总量的25.3%。
从输入地看，2009年在东部地区务工的外出农民工为9076万人，比上年减888万人，下降8.9%，占全国外出农民工总数的62.5%，比上年降低8.5个百分点；在中部地区务工的外出农民工为2477万人，比上年增加618万人，增长33.2%，占全国外出农民工总数的17%，比上年提高3.8个百分点；在西部地区务丁的外出农民工为2940万人，比上年增加775万人，增长35.8%，占全国外出农民工总数的20.2%，比上年提高4.8个百分点。
从性别看，男性外出农民工占65.1%，女性占34.9%。从年龄看，外出农民工以青壮年为主。其中，16～25岁占41.6%，26～30岁占20%，31～140岁占22.3%，41～50岁占11.9%，50岁以上的农民工占4.2%，从婚姻状况看，已婚的外出农民工占56%，未婚的占41.5%，其他占2.5%。
在外出农民工中，文盲占1.1%，小学文化程度占10.6%，初中文化程度占64.8%，高中文化程度占13.1%，中专及以上文化程度占10.4%。高中及以上文化程度比重比上年提高1.7个百分点，占23.5%。分年龄组看，低年龄组中高学历比例要明显高于高年龄组，30岁以下各年龄组中，接受过高中及以上教育的比例均在26%以上，其中，21～25岁年龄组中接受过高中及以上教育的比例达到31.1%。
2009年，外出农民工月平均收入为1417元，比上年增加77元，增长5.7%。外出农民工月均收入在600元以下的占2.1%；600～800元的占5.2%；800～1200元的占31.5%，1200～1600元的占33.9%；1600～2400元的占19.7%；2400元以上的农民工占7.6%。

2009年，全国“31～50岁”的外出农民工约为( )。

A．8000万人

B．5000万人

C．3000万人

D．1000万人