发电机为了防止外部发生故障而装设过流保护，当发电机内部故障时过流保护是不会动作的。

固体氧化物燃料电池(SOFC)以固体氧化物为电解质。其工作原理如图所示：下列关于同体燃料电池的有关说法正确的是

A. 电极b为电池负极，电极反应式为 O₂+4e^-=2O^2-

B. 固体氧化物的作用是让电子在电池内通过

C. 若H₂作为燃料气，则接触面上发生的反应为 H₂+2OH^--4e^-=2H⁺+H₂O

D. 若C₂H₄作为燃料气，则接触面上发生的反应为 C₂H₄+6O^2-+12e^-=2CO₂+2H₂O

依次填入下列各句中横线上的词语，恰当的一组是[ ]

阅读优秀作品， __________ 其语言，感受其思想、艺术魅力，不仅可以__________ 大自然和人生的多姿多彩，还可以激发__________ 自然、热爱生活的感情。

A．品味　体味　珍爱

B．品评　体验　珍惜

C．品评　体验　珍爱

D．品味　体味　珍惜

There are many things people do with their spare time.Have you ever thought about tuning(调音)your own piano for fun and profit？Are you a piano teacher or player who really does not want the expense of hiring a piano tuner and feels that you could do it yourself with a little training？Well，this is your lucky day.All you need are the right tools，a piano and patience.

So，why would I want to tune my piano？There are many reasons for tuning your own piano.

·It is a very pleasant thing to do.

·You can make up to  $80 each time tuning other people's pianos.

·There are millions of pianos in the world and thousands of new ones are being sold every day.There are not enough piano tuners available to tune them all.

·You can provide a valuable service for friends，family and others.

·You can teach yourself very cheaply and then develop it into a part­time or full­time business.

You may have thought that only a trained expert could do this，someone who had devoted years of study and developed a sense of perfect pitch(音高)．In the past，tuning a piano was as much an art form as it was a technology exercise，but now the balance is swaying(摇动) more towards the technology and the final result is as good or even better than tuning by ear.

A few simple tools and a laptop computer with tuning software are all that are required.The real secret is the tuning software，which makes the whole process extremely easy.It means you do not have to train your ears but just look at the laptop screen to know when the piano string is in tune.

I have put together an e­book in my website with all the information you need to get started tuning your own piano, where to get the free software and where to buy the tools.

I hope I have inspired you to think about piano tuning and actually give it a go.You will find it a very rewarding and pleasant activity even if it remains just a hobby.

小题1:The writer asks two questions in the first paragraph to ________.

A．show his doubt on the topic

B．ask readers to answer the questions clearly

C．encourage readers to make comments on the topic

D．attract readers to more information on this topic小题2:According to the passage，why should you learn to tune pianos?

A．To offer help to piano tuners.

B．To save money and earn money as well.

C．Because it can help you make a piano yourself.

D．Because it can help you learn how to play the piano.小题3:What makes piano tuning easier now?

A．Advanced technology.

B．More effective training.

C．More chances of practicing.

D．Traditional tuning methods.小题4:If you want to get the tuning software and tools，you can ________.

A．get them for free from the piano sellers

B．buy them from the writer's online shops

C．make them yourself according to the passage

D．surf the writer's website for the information小题5:In the last paragraph，the writer mainly wants to show that ________.

A．one must be active to play the piano

B．piano tuning will be popular in the future

C．it's valuable to take piano tuning as a hobby

D．it's difficult to tune pianos without professional training

下列不属于桂林古八景的是（）

A、栖霞真境

、B、訾洲烟雨

C、塔山清影

D、尧山冬雪貌

通常来讲，通过我们自己所做的所经历的事情来认识自我的方法是（）。

A.比较法

B.自省法

C.经验法

D.纵向比较法