表速相同，高度升高，飞行M数（）。 A.增大 B.减小 C.不变

阅读理解。

    New rules and behavior standards (行为规范) for middle school students came out in March. Middle

school is going to use a new way to decide who the top students are. The best students won't only have

high marks. They will also be kids who don't dye (染) their hair,smoke or drink. The following are some

of the new rules.

    Tell the truth. Have you ever copied someone else's work on an exam? Don't do it again! That's not

something an honest student should do. If you have played computer games for two hours in your room,

don't tell your parents you have done homework.

     Do more at school. Good students love animals and care for other people. April is Bird-Loving Month

in our country. Is your school doing anything to celebrate?You should join! That way, you can learn more

about animals and how to protect them. When more people work together, it makes it more fun for

everyone. Have you ever quarreled with your teammates when your basketball team lost? Only working

together can make your team stronger. Be friendly to the people you are with. Try to think of others, not

only yourself.

     Be open to new ideas. Have you ever thought that people could live on the moon? Perhaps you'll discover

Earth II someday. Don't look down on new ideas. Everyone's ideas are important. You should welcome

them, because new ideas make life better for everyone. Protect yourself. Has someone ever taken money

from one of your classmates? Don't let it happen to you. If you have to go home late,you should let your

parents know. Use the Internet carefully. The Internet can be very useful for your studies. But some things

on the Internet aren't for kids, so try to look at Web pages that are good for you. You can use the Web for

fun or homework. Can't you find any good Web sites for children? Here are some:

      http://kids.eastday.com/     http://www.chinakids.net.com/   http://www.cycnet.com

1. The school new rules will help kids by telling them ___. [ ]

A. how they can study well

B. how to learn English

C. what is right and what is wrong

D. how they can protect themselves

2. According to the passage,which of the following is NOT true? [ ]

A. Take care of yourself when you are out.

B. Tell the truth, even when you are wrong.

C. Keep some animals to protect them.

D. Use the Internet, but keep away from bad things.

3. The main idea of the third paragraph is about ___. [ ]

A. making the team stronger

B. working together with others

C. being a good friend to others

D. getting on well with others

4. Good Web sites for children can ___. [ ]

A. be a waste of time

B. help them with their studies

C. do homework for them

D. make life easier

5. The passage tells us how to ___. [ ]

A. be top students

B. do more at school

C. care for others

D. use the Internet

在一定温度下，冰醋酸加水稀释过程中，溶液的导电能力I随加入水的体积V变化的曲线如图所示。请完成下列问题：

（1）“O”点导电能力为0的理由是____________。

（2）a、b、c三点处，溶液的c（H⁺）由小到大的顺序为____________。

（3）a、b、c三点处，电离程度最大的是____________。

（4）若使c点溶液中c（CH₃COO^-）增大，溶液c（H⁺）减小，可采取的措施是：①____________；②____________；③____________。

次级精母细胞（）

A.形似蝌蚪，分头、颈、尾三部分

B.迅速完成第二次成熟分裂，形成精子细胞

C.经形态改变形成精子

D.位于精原细胞的内侧，胞体大

E.紧靠基膜，胞体小

从印刷术诞生以来．人们就一直停留在二维平面上，而3D打印技术则使“立体印刷”成为可能。2012年的最后一天，全国首家3D打印照相体验馆落户西安高新区。3D打印技术实现了( )

①对客观事物已认知规律的再创新          ②从自在到人为事物联系的再跨越

③在已有事物联系基础上的再创造         ④对已知事物肯定基础上的再否定

A．①②

B．②③

C．③④

D．①④

When Newsweek recently asked 1,000 U. S. citizens to take America’s official citizenship test, 29 percent couldn’t name the vice president. Seventy-three percent couldn’t correctly say why we fought the Cold War. Forty-four percent were unable to define the Bill of Rights. And 6 percent couldn’t even circle Independence Day on a calendar.

Don’t get us wrong: civic ignorance is nothing new. For as long as they’ve existed, Americans have been misunderstanding checks and balances and misidentifying their senators. And they’ve been lamenting the ignorance of their peers ever since pollsters started publishing these dispiriting surveys back in Harry Truman’s day. According to a study by Michael X. Delli Carpini, dean of the Annenberg School for Communication, the yearly shifts in civic knowledge since World War II have averaged out to "slightly under 1 percent. "

But the world has changed. And unfortunately, it’s becoming more and more inhospitable to incurious know-nothings—like us. To appreciate the risks involved, it’s important to understand where American ignorance comes from. In March 2009, the European Journal of Communication asked citizens of Britain, Denmark, Finland, and the U.S. to answer questions on international affairs. The Europeans outdid us. It was only the latest in a series of polls that have shown us lagging behind our First World peers.

Most experts agree that the relative complexity of the U. S. political system makes it hard for Americans to keep up. In many European countries, parliaments have proportional representation, and the majority party rules without having to "share power with a lot of subnational governments," notes Yale political scientist Jacob Hacker. In contrast, we’re saddled with a nonproportional Senate; a tangle of state, local, and federal bureaucracies; and near-constant elections for every imaginable office (judge, sheriff, school-board member, and so on). "Nobody is competent to understand it all, which you realize every time you vote," says Michael Schudson, author of The Good Citizen. "You know you’re going to come up short, and that discourages you from learning more. "

It doesn’t help that the United States has one of the highest levels of income inequality in the developed world, with the top 400 households raking in more money than the bottom 60 percent combined. As Dalton Conley, an NYU sociologist, explains, "it’s like comparing apples and oranges. Unlike Denmark, we have a lot of very poor people without access to good education, and a huge immigrant population that doesn’t even speak English. " When surveys focus on well-off, native-born respondents, the U. S. actually holds its own against Europe.

For more than two centuries, Americans have gotten away with not knowing much about the world around them. But times have changed—and they’ve changed in ways that make civic ignorance a big problem going forward. We suffer from a lack of information rather than a lack of ability. Whether that’s a treatable affliction or a terminal illness remains to be seen. But now’s the time to start searching for a cure.

The author implies in Paragraph 3 that（）

A. it is all the more important for Americans to know the less friendly world

B. the risks in remaining ignorant in a fasting changing world will be costly

C. America should learn from Europe in training and educating its citizens

D. Americans’ knowledge about the world has been increasing slowly each year