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人造太阳
何 平
①前不久，一条新闻引起全世界关注：中国科学院等离子体物理研究所研制的“人造太阳”调试成功，年内即可试发电。
②“人造太阳”？难道真要在地球上造一个太阳？当然不是！“人造太阳”是指科学家利用太阳核反应原理，为人类制造一种能提供能源的机器——人工可控核聚变装置，科学家称它为“全超导托克马克试验装置”。
③太阳的光和热，来源于氢的两个同胞兄弟——氘和氚（物理学叫氢的同位素）在聚变成一个氦原子的过程中释放出的能量。“人造太阳”就是模仿这一过程。
④氢弹是人们最早制造出的“人造太阳”。但氢弹的聚变过程是不可控的，它瞬间释放出的巨大能量足以毁灭一切。而“全超导托克马克试验装置”却能够稳定控制核聚变，使聚变产生的能量缓缓输出，转化为人们可持续使用的电能。
⑤核聚变反应，首要条件是高温高压。太阳中心的温度高达1500万摄氏度，压强达到3000多亿个大气压。在这样的高温高压下，太阳的聚变反应非常容易。但在地球上可不容易，因为用任何一种材料制作的容器都无法耐受这样的高温高压。
⑥怎么办？科学家们想到了用磁场做容器。从氢弹爆炸至今，科学界用了60年的努力，目前已成功地在磁场容器中将温度提高到4亿至5亿摄氏度，然后投入氘氚产生聚变反应。但由于很难把这种高温长时间维持下去，所以全世界30多个国家上百个实验装置的聚变放电时间都很短！少则几秒，长的也不过数百秒。我国从1965年研究“人造太阳”开始，如今已能使放电时间持续千秒以上。
⑦所以，科学家说，建设核聚变电站投入民用，至少要再等上50年时间。但等待是值得的！现在地球上的石油、煤炭等化石能源至多可用200年时间，其中石油不足50年。即使目前核裂变电站使用的铀燃料，全世界也只能再开采60年。用这些材料做能源还有个致命弱点——环境污染！
⑧相反，氘和氚却是清洁能源，如空气中平时就有氘和氚。所以不用担心聚变反应会产生废气、废渣和放射性污染等问题。有人担心电站爆炸，但科学家说，聚变在磁场中进行，维持温度已很不易，只要稍微马虎，温度就会降下来，聚变就停止了，因此爆炸的可能性是零。
⑨氘和氚是取之不尽用之不竭的能源。世界海洋中大概蕴藏了40万亿吨氘。如果全部用于聚变反应，释放的能量足够人类使用几百亿年，这比太阳的寿命还要长了。
【小题1】选文的说明对象是什么？它的总体特征是什么？（3分）
【小题2】选文第③段的目的在于说明什么？（2分）
【小题3】第⑥自然段与第⑦自然段能不能互换？为什么？（3分）
【小题4】氘和氚是清洁的能源，这样说的根据是什么？在自然界中，你认为还能开发哪些目前还未利用的清洁的能源？简要说说能开发的理由。（4分） 查看习题详情和答案>>
What is the World Wide Web? The World Wide Web has been the most popular development of the Internet. The Web is like a big electronic book with millions of pages. These pages are called homepages. You can find information about almost anything in the world on these pages. For example,(B)you can use the Internet instead of a library to find information for your homework. You can also find information about your favourite sports or film stars, talk to your friends or even do some shopping on the Internet. Most pages have words, pictures and even sound or music.
What is e-mail?(C) 电子邮件是给别人发送信息的一种方法。 It's much quicker and cheaper than sending a letter. If you want to send e-mails, you must have an e-mail address. This address must have letters and dots(点 ) and an ‘@’( meaning ‘at'). This is what an address looks like: Emily @ star. net. Write a message, type in the person's e-mail address, and then send the message on the Internet. People don't need to use stamps, envelopes or go to the post office since the invention of the Internet. Quick. easy and interesting--that's the Internet!
小题1:在A的空白处填入适当的词，使句意完整，上下文通顺： 小题2:将(B)句译成汉语：_____________________________________________________小题3:将(C)句译成英语：_____________________________________________________小题4:从文中找出所给句子的同义句：Sending a letter is much slower and dearer than it.__________________________________________________________
小题5:从文中找出最能表达英特网特点的句子：
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综合阅读
Many American children love their mothers' apple pies．So(A)________ adults(成年人)!Apple pie is one of the most famous dessert(餐后甜占)in America．
You can buy it in lots of restaurants．(B)Apple pie is easy to make, so many people cook it at home(C)________．You just need apples, flour(面粉), sugar, butter and spices．
To make an apple pie, first cut up the apples into pieces．Then mix(D)them with spices and put them in a pie tin．Next mix butter, sugar and flour．Put the mixture on the apple pieces and bake(烤)the pie for about 45 minutes．The smell of apple pie cooking is great．People usually eat apple pie with ice cream．
In winter, a piece of warm pie is a wonderful way to warm up on a cold day．In summer, a plate of cold pie is(E)一种降温的好方法．
There are many different ways to make apple pies．Some families have their own secret(秘密的)ways and don't tell other people about them．
Pies made with berries(浆果)are also very popular in America．But apple pie perhaps is the dessert that everyone loves most．
1．在(A)和(C)的空白处填入适当的单词________；________
2．将画线部分(B)改写为Apple pie is ________ to make，
3．画线部分(D)指代的是_______________________________
4．将画线部分(E)译成英语_____________________________
5．从文中找出能解释apple pie的最佳短语。______________
He knows that things are different now. But he never forgets the old days. He likes to talk about them. He
often talks about his favourite birds, the robins (欧洲的一种小鸟). "When I was a boy, these houses were not
here. There were wide fields and tall trees. Every spring the robins would come. Thousands of them would fly
up to the north from the south. They spent the winter in the south. Some would build their nests (巢) in the trees
near our houses. Then people started to cut down trees, and they built more houses. The robins stopped coming.
They couldn't build their nests near our houses because there were no trees."
"Now there are too many houses and too many roads. There are no places for the robins. They do not come
any more."
B. the old days
C. his life now
D. his family
B. the west
C. the north
D. the east
B. Some people
C. The robins
D. Some dogs
B. planted
C. bought
D. watered
B. there were many houses there in the old days
C. the robins can make their nests without trees
D. Mr. Ellis is not happy with the changes there