首页
外语
计算机
考研
公务员
职业资格
财经
工程
司法
医学
专升本
自考
实用职业技能
登录
外语
They sparkle and glitter in the light. No other rocks are so hard. They are very valuable. It might cost thousands and thousands
They sparkle and glitter in the light. No other rocks are so hard. They are very valuable. It might cost thousands and thousands
admin
2010-02-20
13
问题
They sparkle and glitter in the light. No other rocks are so hard. They are very valuable. It might cost thousands and thousands of dollars to buy just one. Most are found in the ground. The largest ore ever discovered is as big as a man’s fist. But most are tiny.
They’re diamonds!
For hundreds of years men have risked their lives searching for diamonds. To many the discovery of this glittering treasure has seemed more important than the discovery of new lands. Fairy stories tell of brave knights who battled fierce dragons and evil wizards to win kingdom rich with diamonds. In the Tower of Ion- don in England, there is a very special room protected by guards. There, inside a thick glass case, are jeweled crowns once worn by kings and queens. People from all over the world come to see the shimmering diamonds and other precious stones that shine from behind the glass.
Most diamonds seem to flash with a kind of white fire. But there are diamonds that sparkle in other colors, too. Sometimes diamonds are discovered in gravel at the bottom of rivers and streams. (To get these diamonds, the gravel is sucked up through giant hoses that act like vacuum cleaners.) Diamonds are found in rivers, on land, and in great stretches of hot desert sand. A few small ones are even found or near meteorites that strike the ground from outer space.
But most diamonds are found in rocks deep inside the diamond mines of Africa. The diamonds were made millions and millions of years ago when flaming volcanoes melted a mineral called carbon which was a part of these rocks. Gigantic earthquakes shook the rock and pressed them tightly together. The hot melted carbon in the rock squeezed at the same time--squeezed so tightly that by the time it cooled, it had changed into the lovely hard gems called diamonds.
To get at these valuable diamond rocks, workers ride in an elevator that goes down and down into the blackness far below the ground. Tunnels connect this deep shaft with the openings--called pipes--inside the ancient volcanoes.
When they are first dug from the mines, diamonds don’t glitter or sparkle as they do when we see them in rings or other jewelry. They look more like dull bits of glass. A man who knows all about diamonds--a diamond cutter--must cut them just right. Diamonds are so hard that nothing can cut them except the edge of an- other diamond.
Using his diamond-edged tools, the diamond cutter carefully removes tiny pieces so that the diamond will have many sharp edges and smooth surfaces--like little windows. It is because of these shaft edges and smooth surfaces that the diamond reflects light, sparkles and flashes with tiny bursts of color, and seems almost ablaze with fire. Diamond cutters often use diamond saws. The fine powder--diamond dust--that is left after the sa- wing is done can be used in a kind of sandpaper to polish the sparking gems.
Not all diamonds are clear enough or pretty enough or large enough to be made into jewelry. But because they are so hard, they can be used for other things, such as points for drills and needles for record player. These diamonds are called industrial diamonds. Some of them are man made. Carbon is heated until it is hot and then squeezed. If men ever learn how to make it hot enough and to squeeze it tightly enough, they will probably be able to make big diamonds. Then maybe diamonds will be cheap enough to use as buttons on your shirt or coat! (610)
Diamonds are so hard that only _____ can cut it.
选项
A、a man who knows all about diamonds
B、diamond-edged tools
C、a special cutter
D、diamond cutter
答案
B
解析
事实细节题。本题答案的依据在文章倒数第三段:Diamonds are so hard that nothing can cut them except the edge of another diamond.A项和D项实际上是同一概念,作为钻石切割者,没有工具,他们也无法切割钻石。C项特殊工具不准确,因此舍弃。
转载请注明原文地址:https://kaotiyun.com/show/l4vO777K
0
专业英语八级
相关试题推荐
A、Thegrowingcrisisofinadequateretirementpensionsforthefuture.B、Theproblemofprovidingadequatemedicalcareforthe
A、Nighttimetemperaturesdipbelow50degrees.B、Plentifulwindcurrentsmakesomeoutdoorsactivitiespossible.C、Springusuall
Joyandsadnessareexperiencedbypeopleinallculturesaroundtheworld,buthowcanwetellwhenotherpeoplearehappyord
Scienceisadominantthemeinourculture.Sinceittouchesalmosteveryfacetofourlife,educatedpeople,needatleastsome
A、Thereare200vehiclesforeverykilometerofroadway.B、Ithasadensepopulation.C、Therearemanymuseumsandpalaces.D、It
Wecanbeginourdiscussionof"populationasglobalissue"withwhatmostpersonsmeanwhentheydiscuss"thepopulationproble
Wecanbeginourdiscussionof"populationasglobalissue"withwhatmostpersonsmeanwhentheydiscuss"thepopulationproble
Whenyoungcollegegraduatesdecidewheretomove,theyarenotjustlookingattheusualsuspects,likeNewYork,Washingtonan
I’mMargeryHooper,yourcoursecoordinator.I’dliketowelcomeyoualltoGrangeManorSummerMusicschool.Ihopeyou’llenjo
随机试题
俄罗斯的普通教育分为相互联系的几个阶段()
牙体缺损的准确定义是
综合布线系统中水平布线电缆总长度的允许最大值是:(2003,118)
F面不属于网络安全特征的是()。
当单位遭遇金融危机袭击时,你会()。
【2015年福建.单选】为了改变传统课程过分强调学科本位的现象.新课标注重联系学生经验和生活实际,提倡和追求不同学科间的彼此联系,这体现的新课程结构特征是()。
党的十八大报告中指出,加强社会主义核心价值体系建设,是扎实推进社会主义文化强国建设的重要举措。下列关于社会主义核心价值体系的说法不正确的是()。
下列各项中不属于《行政许可法》的调整范围的是()。
圈养动物是比野生动物更有意思的研究对象。因此,研究人员从研究圈养动物中能够比从研究野生动物中学到更多的东西。上面的论证依赖于下面哪一个假设?
保证法律实施的是()。
最新回复
(
0
)