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    地球上的第一个动物 the first animals on Earth 【查看更多】

     

    题目列表(包括答案和解析)

    1．很长时间以前________

    2．地球上的第一个动物________

    3．不同种类的恐龙________

    4．重大约三公斤________

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    阅读下文，完成下面题目。
    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）

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    先阅读短文，再在答题卡上相应的空白处写出各单词的正确形式。单词的第一个字母已给出。

    I worked at a Care Center where most of the people are elderly. About a year and a half ago a 59-year-old lady came to us who had cancer. She had to have her right leg cut off and she didn’t have a family to take care of her after the o_1._.

    This lady was a quiet lady who mostly stayed a_2._. But in the afternoons, when she was feeling w_3._, she would go to help the other people in the home. She would v_4._ a lady who was blind and read to her. She would go into the room of a young girl with severe cerebral palsy(脑瘫) and sing to her.

    She p_5._ away last Wednesday and after her death, stories are coming forward of her quiet acts of k_6._ in her own hour of sadness.

    We n_7._ know what we have upon others. She had every r_8._ to be bitter, to be angry, or to be sorry for her own fortune. But she wasn’t. She didn’t have a family and probably felt forgotten, but her small and quiet acts of service had a great influence upon the whole Care Center.

    Each of us feels b_9._ than before for having know her. We have decided to be more aware(意识) of the service that we can o_10._ to others.

     

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    先阅读短文，在横线上写出各单词的正确形式，单词的第一个字母已给出。
           One day Harvey's wife was cleaning out a cupboard.
           "Look at all these umbrellas," Harvey's wife said to him. "There are eight and they all b    1     ."
           "I'll take them all to the umbrella shop and have them repaired," Harvey said. "They are too good to t    2    
    away." 
           Harvey took the eight umbrellas to the shop and l     3      them there. The shopkeeper said, "They'll be
    r    4     tomorrow."
           That evening Harvey went home from the office by bus as he u    5     did. He sat next to an old woman.
    She had an umbrella on the floor between the s    6     . When the bus reached his stop, he picked up her
    umbrella and stood up.
           "Hey!" the woman said, "That umbrella b    7     to me."
           "I'm so sorry." Harvey said, giving it to her. "Please excuse me for taking your umbrella by m    8    ."
           The next day he collected the umbrellas from the umbrella shop and got on the bus. As he sat down, a
    v    9     behind said, "You have certainly had a s   10     day!" He turned around and saw the woman whose
    umbrella he had almost taken the day before.
    1.                2.                3.                4.                 5.                
    6.                7.                8.                9.                 10.             

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             请把下列的单词中的第一个字母变成别的字母，使它成为一个另外的单词，并将其汉语意思写在后面的横线上。 注意：只能变第一个字母，后面的读音要相同。
    1. foot  2. talk    3. teach  4. mouse   5. call   6. cake  7. say       8. right
    9. sun  10. cook 11. cap  12. too      13. bit1 4. gate   15. give  16. kind
    17. main18. sat19. pine20.know
    1. ________ ________   2. ________ ________  3. ________ ________
    4. ________ ________   5. ________ ________  6. ________ ________
    7. ________ ________   8. ________ ________  9. ________ ________
    10. ________ ________11. ________ ________12. ________ ________
    13. ________ ________14. ________ ________15. ________ ________
    16. ________ ________17. ________ ________18. ________ ________
    19. ________ ________20. ________ ________

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