题干

下列结合实验现象的反应方程式正确的是()

A:切开的金属Na暴露在空气中,光亮表面逐渐变暗2Na+O2=Na2O2

B:向AgC1悬浊液中滴加Na2S溶液,白色沉淀变成黑色2AgC1+S2-=Ag2S↓+2C1-

C:Na2O2在潮湿的空气中放置一段时间,变成白色粘稠物2Na2O2 +2CO2=2Na2CO3+O2

D:向NaHCO3溶液中加入过量的澄清石灰水,出现白色沉淀2HCO3-+Ca2++2OH-=CaCO3↓+CO32-+2H2O

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答案(点此获取答案解析)

B

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阅读下列短文,从每题所给的四个选项(A、B、C和D)中选出最佳选项。

    There is a popular Chinese saying that “Fair skin(皮肤) will make up for three flaws(缺陷)”. This mentions the fact that in Chinese culture, it is believed that people who have fair skin are more beautiful. In Western culture, however, the opposite is true — many Westerners think tanned skin is prettier. The example shows that different cultures have different ideas of what they think is beautiful. These cultural meanings of the beauty, however, are no longer important. As more and more people travel overseas, ideas about beauty are being shared among cultures. The Internet has also made it easier for people to share different types of beauty since people are always posting pictures on social media. The result is an ever-changing idea of what is considered beautiful.

    The cultural practice of ear piercings, for example, has become a part of modern day culture.

    In Kenya, it is a tradition among Masai men and women to pierce and then make their ear

    lobes( 耳 垂 ) longer using ivory and wood or stones. They then wear colorful things on their ear lobes. This is a common practice since longer ear lobes are seen as a sigh of beauty. This tradition has now found its way into present-day culture. Nowadays, this might still seem unusual to some, but with more and more well-known actors and film stars showing off their longer ear lobes, it will finally become more fashionable.

    It is understood that different cultures around the world have different ways of showing beauty. However, since we now live in a worldwide society, people's views about beauty are always changing. With the help of the Internet, people are now able to easily borrow ideas from other cultures to help them stand out. So what new fashions can we expect to see in the future?