发光二极管的内部存在一个PN结，具有单向导电性，当发光二极管在正向导通时会发光，光的

阅读理解。

Good morning, class!

     We know that there are too many net bars around us. The Internet is popular and it makes our lives

colorful. Many of us like going online very much because we can learn how to use the computer and get

more information from the Internet. We can learn English. We can read some good newspapers and

magazines. It can make us clever in playing computer games. We can send E-mails to our friends quickly. We can chat(聊天) freely online with our friends. It can help us get in touch with people from all over the world.

     But some students spend too much time in playing computer game and some stay in the net bars all day and all night. Teenagers even get to have boyfriends or girlfriends online. They write too many letters to

each other. It takes them to much time to chat online so they do worse and worse in their lessons and they don’t study well any more. I think we mustn’t get online when it is time for us to study. We can do it in

summer or winter holidays. We should get online with adults(成人)--our teacher or parents.

     At the same time, if we have lots of free time, we can do some out-of-class activities at school. We

usually have activities from 4:50 to 5:50 in the afternoon. We have different kinds of activities. If you are

interested in sports,you can play basketball or football.We can go to the English Corner.We can practice

talking in English there. We hope we can spend more time on our subjects or on such activities that we

can learn a lot from and less time on the Internet.

     Thank you for listening to me. That’s all.

1.The short passage is about _______.

A. going online              

B. how to communicate with others

C. how to spend our free time    

D. different kinds of activities

2. The Internet can make our lives _______.

A. helpful and important        

B. enjoyable and interesting

C. enjoyable but expensive      

D. different kinds of activities

3. _______ is not good.

A. Sending E-mails            

B. Reading newspapers and magazines online

C. going on line with adults    

D. Spending all day in the net bars 

4. Playing computer games_______.

A. gives us lots of information    

B. makes our studies worse

C. makes us more clever          

D. is harmful to our health

5. Which of the following is NOT right?

A. There are too many net bars in the cities.

B. We can learn English from the Internet.

C. We mustn’t get online when we are studying at school.

D. We cannot do out-of-class activities from 4:50 to 5:50 p.m.

心脏骤停最主要的诊断标准是（）。

A.意志丧失

B.动脉搏动消失

C.呼吸缓慢

D.心音消失

E.全身发绀

男性，52岁，5小时前右上腹部挤压伤。查体：中上腹及背部压痛。尿检查正常。X线检查脊柱正常，膈下未见游离气体，腹膜后有少量积气。可能的诊断为

A．胃挫伤

B．十二指肠穿孔

C．小肠损伤、穿孔

D．胆道损伤

E．横结肠损伤、穿孔

读下列两幅地图，回答下列各题．

（1）从地理位置看，日本、俄罗斯两国都位于______（南或北）半球．

图中A______岛，B______煤矿C______油田，

D______海

（2）从资源和工业分布情况看，日本资源______，其工业主要集中分布在______沿岸．俄罗斯的工业主要分布在______（大洲）部分，从自然资源条件看，该国发展工业的有利条件是______．该国首都是______，

波罗的海沿岸重要港口是______．

某银行针对待建设的网络工程中存储子系统提出的要求是：用户存取速度快、系统可用性最高、可进行异地存取和备份。针对该用户需求，规划师在考虑服务器集群技术时，选用______是最合适的。若要求某服务器系统年停机时间小于等于45分钟，则该服务系统的可用性至少达到______。

A．服务器镜像技术
B．服务器双工技术
C．应用程序错误接管集群技术
D．容错集群技术