发电机逆功率保护的主要作用是（）。A.防止发电机进相运行 B.防止发电机低负荷运行

公式中，f代表().

A．建设期价格上涨指数

B．通货膨胀率

C．银行利率

D．行业基准利润率

柴油机一般由两大机构，（）大系统组成。

A、两

B、三

C、四

D、六

This year some twenty-three hundred teenagers（young people aged from 13 —19）from all over the world will spend about ten months in U. S. homes. They will attend U.S. schools, meet U.S. teenagers, and form impressions of the real America. At the same time, about thirteen hundred American teenagers will go to other countries to learn new languages and gain a new understanding of the rest of the world.

Here is a two-way student exchange in action. Fred, nineteen, spent last year in Germany with George’s family. In turn, George’s son Mike spent a year in Fred’s home in America.

Fred, a lively young man, knew little German when he arrived, but after two months’ study, the language began to come to him. The school was completely different from what he had expected — much harder. Students rose respectfully^① when the teacher entered the room. They took fourteen subjects instead of the six that are usual in the United States. There were almost no outside activities.

Family life, too, was different. The father’s word was law, and all activities were around the family rather than the individual. Fred found the food too simple at first. Also, he missed having a car.

“Back home, you pick up some friends in a car and go out and have a good time. In Germany, you walk, but you soon learn to like it.”

At the same time, in America, Mike, a friendly German boy, was also forming his idea. “I suppose I should criticize^② American schools,” he says. “It is far too easy by our level. But I have to say that I like it very much. In Germany we do nothing but study. Here we take part in many outside activities. I think that maybe your schools are better in training for citizens. There ought to be some middle ground between the two.”

Notes:

①    respectfully  adv. 尊敬地，谦恭地

②    criticize  vt. 批评，责备

Choose the best answers according to the above:

小题1:This year       __ teenagers will take part in the exchange programme between America and other countries.

A．twenty-three hundred

B．thirteen hundred

C．over three thousand

D．less than two thousand小题2:The whole exchange programme is mainly to        __.

A．help teenagers in other countries know the real America

B．send students in America to travel in Germany

C．let students learn something about other countries

D．have teenagers learn new languages小题3:What is particular in America schools is that        __.

A．there is some middle ground between the two teaching buildings.

B．there are a lot of outside activities

C．students usually take fourteen subjects in all

D．students go outside to enjoy themselves in a car小题4:After experiencing the American school life, Mike thought        __.

A．a better education should include something good from both American and Germany

B．German schools trained students to be better citizens

C．American schools were not as good as German schools

D．the easy life in the American school was more helpful to students

由域名查询IP地址的过程分为递归查询和迭代查询两种，其中递归查询返回的结果为（17），而迭代查询返回的结果是（18）。

空白处（18）应选择（）

A.其他服务器的名字或地址

B.上级域名服务器的地址

C.域名所对应的IP地址或错误信息

D.中介域名服务器的地址

下面是一个Applet程序，其功能是建立一个图形用户界面的窗口，包括一个文本显示区和一个按钮，点击按钮，可以在文本区已有的文本基础上追加显示10条“Welcome to the NCR Examination!”信息，并且文本区由滚动条控制文本的上下滚动。请改正程序中的错误(有下划线的语句)，使程序能输出正确的结果。 注意：不改动程序的结构，不得增行或删行。 程序运行结果如下：

import javax.swing.* ； import java.awt.*； import java.awt.event.*； /* ＜applet code="ex10_3.class"width = 800 height=400＞ ＜/applet＞ */ public class ex10_3 extends JApplet { JButton jb = new JButton("Add Text")； JTextPane itp = new JTextPane()； public void init() {jb.addActionListener(new ActionListener() {public void actionPerformed(ActionEvent e) { for(int i = 1；i＜10；i++) jtp.getText(jtp.setText()+"Welcome to the NCR Examination!\n");}})；Container cp = getContentPane()；cp.add(new JScrollPane(jtp))；cp.add(BorderLayout.SOUTH,jtp)； } public static void main(String[]args) { ex10_3 obj10_3=new ex10_3()； String str = obj10_3.getClass().toString()； if(str.indexOf("class") != -1) str = str.substring(6); JFrame frm = new JFrame(str); frm.addWindowListener(new WindowAdapter() { public void windowClosing(WindowEvent we) {System.exit(O); } }); frm.getContentPane().add(ex10_3); frm.setSize(300, 400); frm.setVisible(true); } } ex10_3.html ＜HTML＞ ＜HEAD＞ ＜TITLE＞ex10_3＜/TITLE＞ ＜/HEAD＞ ＜BODY＞ ＜applet code="exl0_3.class" width=800 height=400 ＞ ＜/applet＞ ＜/BODY＞ ＜/HTML＞