真题解析:南非黑钻 南非黑钻是相对较新的一道真题,虽然作为一道reading and writing 四选一的fill in the blank 真题,它的四个选项现在并不可考,这道题本身还是有很多值得讲的要点的。所以来和大家分享一下。 文章梗概本文讲科学姐们在非洲发现一种神秘的黑色钻石,可能是来自外太空。文章介绍了钻石的具体情况,和科学家们的一些发现。 真题原文An exotic type of diamond may have come to Earth from outer space, scientists say.Called carbonado or "black" diamonds, the mysterious stones are found in Brazil and the Central African Republic. They are unusual for being the colour of charcoal and full of frothy bubbles. The diamonds, which can weigh in at more than 3,600 carats, can also have a face that looks like melted glass. Because of their odd appearance, the diamonds are unsuitable as gemstones. But they do have industrial applications and were used in the drill bits that helped dig the Panama Canal. Now a team led by Stephen Haggerty of Florida International University in Miami has presented a new study suggesting that the odd stones were brought to Earth by an asteroid billions of years ago. The findings were published online in the journal Astrophysical Journal Letters on December 20. The scientists exposed polished pieces of carbonado to extremely intense infrared light. The test revealed the presence of many hydrogen-carbon bonds, indicating that the diamonds probably formed in a hydrogen-rich environment—such as that found in space.