题干

如图  为直流电源, 为浸透饱和氯化钠溶液和酚酞试液的滤纸, 为电镀槽,接通电路后发现 上的c点显红色,为实现铁上镀锌,接通 后,使c、d两点短路.下列叙述正确的是 (  )

A:a为直流电源的负极

B:c极发生的反应为2H++2e═H2

C:f电极为锌板

D:e极发生还原反应

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B

同类题3

任务型阅读

    Global Positioning System (GPS) is now a part of everyday driving in many countries. It is a space-based system that provides position and time information in all weather conditions. GPS can help people get to where they want to go.____When this happens, the driver is often to blame. Sometimes a GPS error is responsible. Most often, it is a combination of the two.

    ____Barry Brown, a GPS technologist, took an incident as an example. His friend once flew to an airport in the eastern United States. There he borrowed a GPS-equipped car to use. He wrongly plugged in the home address in the west. It wasn't until he was driving for thirty minutes that he realized it. Mr. Brown says this is a common human error. But he says, “One problem is that GPS has a very small screen and it can just tell you the next turn.____

    “The Normal and Natural Troubles of Driving with GPS” lists several areas where GPS can cause difficulties. They include maps that are outdated, incorrect or difficult to understand. ____GPS may fail due to these reasons and then lead to confusion for the drivers.

    Although GPS sometimes causes difficulties when people are driving, the most attractive point of this system is its 100% coverage on the planet. It is important for you to have to know what you are doing when you use GPS. You need to have the “ability” to be able to use GPS because it sometimes goes wrong.____

A. There are quite a few situations showing the problems of using GPS.

B. That means that it is not really telling you about going to the wrong place.

C. This space-based system is an important tool for civil and commercial users.

D. But sometimes it sends you to the wrong place or leaves you completely lost.

E. They also contain timing problems related to when GPS commands are given.

F. Advances in technology play an active role in modernizing GPS in many ways.

G. To make GPS well used, you need a good understanding of how drivers and GPS work.

同类题4

信息归纳:阅读下文,根据所提供的信息,完成下列表格。

    Your Junior 3 year will finish soon. Do you want to say something about your junior school life? What were the rewards (收获) of the three years? Our readers have their stories to share.

Ben,15,Guangzhou,Guangdong

   I experienced a hard time in Junior 2 when my grades suddenly dropped(下降) a lot. I faced great pressure. In the following summer vacation, I worked hard by studying for 10 hours a day. It was crazy, but when I became one of the top students again, I felt everything had been worthwhile(值得的).

Julie, 13,Beijing

     In July, 2011,I had a trip to the UK with some students and teachers. When we arrived there, the other students and I didn't want to eat the local food. The teachers were worried and tried to make us eat. When we finally finished the meal, the guide said that the world now sees how spoiled(被宠坏的)Chinese kids are. I felt really sorry.

John,14,Hangzhou,Zhejiang

    I lived in a dorm(寝室)during junior school. It was a great challenge since I had never left my parents before that. I had to take care of everything myself. I learned to make my bed and get along with roommates. I also learned to make a schedule to arrange(安排)my time .I've done a good job and I feel proud.


Information Card

Age of Ben

____

Place John is from

____

Time Julie went to the UK

____

How Ben improve his grades

____

Things John has learned during junior school

Make the bed ____

Make a schedule to arrange time