题干

用分子的知识解释下列现象,正确的是(  )


A:带火星的木条在氧气中能复燃,在空气中却不能,说明它们中的氧分子化学性质不同

B:缉毒犬能根据气味发现毒品,是由于分子不断运动

C:变瘪的乒乓球放入热水中能鼓起来,是由于分子受热体积变大

D:​降温能使水结成冰,是因为在低温下水分子静止不动

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答案(点此获取答案解析)

B

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美的启发
      我家住在古城一角,窗外有一块难得的空地,附近的居民竟把它当成了堆垃圾的地方。怎么办?我制了一个“禁止倒垃圾”的木牌插在那里,可人们连看都不看一眼。这里仍旧垃圾成堆,臭气熏天。为此我们一家人伤透了脑筋。
      一个星期天的早晨,爸爸、妈妈嘀咕了一阵,然后兴奋地告诉我一个好主意。我听了,乐得直拍手。于是我们全家一齐动手,先将垃圾铲成一堆,接着从河边挑来石块,砌成一个椭圆形的花坛,再糊上水泥,并在石缝处勾出十分好看的图案,又在花坛的垃圾上面堆上一尺多厚的细土,栽上各种花苗,还就近挖来了两笼翠竹,种在花坛的东西两旁。一天工夫,这儿完全变成了另一番景象。附近的居民______没来这儿倒垃圾,_______纷纷把家里珍贵的花木慷慨地奉献出来,为这小小的花圃增美添色。
       春去秋来,昔日的空地已经是花团锦簇,翠木葱茏,成了古城的一角风景。人们工作之余,便来这儿休息聊天,看书下棋。你瞧,一位小姐姐正坐在花坛边抚弄着琴弦呢!
       窗外,飘散着动人的琴声;窗外,洋溢着沁人心脾的清香;窗外、小鸟在枝头欢乐地歌唱……看着窗外那幅人与自然相映成趣的风景图,我蓦然懂得了:只有用美,才能启发更多的人热爱美,创造美!

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根据短文内容,从短文后的选项中选出能填入空白处的最佳选项,并在答题卡上将该项涂黑。选项中有两项为多余选项。

                                                                                      Pronunciation Tips

           These English pronunciation tips will help you get the most out of your Pronunciation Power program.

★ ____

    For example, “threw” and “through”, although spelled differently, are pronounced the same. Also, identical(相同的)letters or letter clusters(字母组合) in words do not always produce the same sound. For example, the “ough” in “though” and “through” represents a different sound in each word.____

★ Imagine a sound in your mindbefore you say it.

    Try to visualize(想象))thepositioning of your mouth and face.____

★ Listen to and try to imitate thePronunciation Power instructor.

    In addition to listening for specific sounds, pay attention to pauses, the intonation(语调) of the instructor's voice and patterns of emphasis.____.

★ The English language has manydifferent dialects, and words can be pronounced differently.

    It is important, however, that you pronounce words clearly to ensure effective communication.

★ Finally, the Pronunciation Powerprogram is a tool to help you.

    But you must practice what you are learning! Remember that you are teaching your mouth a new way to move. You are building muscles that you do not use in your own language.____Use the program to exercise yourmouth a little bit each day.

a. Read these words over and over againand try to learn them by heart.

b. This can be just as important as the pronunciation of sounds.

c. Learn to practice what you hear, notwhat you see.

d. So you should force yourself to dowhat you really don't like to do.

e. Do not confuse pronunciation of words with their spelling!

f. It is like going to the gym andexercising your body.

g. Think about how you are going to make the sound.