首页
登录
职称英语
[img]2016m12s/ct_eyyjscz2015j_eyyjsccloze_0151_201611[/img] Diamond is the h
[img]2016m12s/ct_eyyjscz2015j_eyyjsccloze_0151_201611[/img] Diamond is the h
游客
2023-10-17
45
管理
问题
Diamond is the hardest naturally occurring substance known. It is the most popular gemstone and because of its extreme 【C1】______(hard), it is also used for various industrial purposes. Scientists are still 【C2】______(sure)of the exact process by which diamonds are naturally formed, but it is certain that both extreme heat and enormous pressure are needed. It is, therefore, likely that diamonds were formed far【C3】be______the Earth’s surface where these conditions exist. The first synthetic diamonds were successfully produced in the 1950s, but the best and largest stones are still those created by nature.
The word ’ diamond’ comes from the Greek ’ adamas’ , which means invincible, but the first definite reference to diamonds occurs in Roman literature of the first century A. D. The diamonds known to the Romans came from India, which was the only 【C4】______(supply)of the stones until the eighteenth century. In 1762, diamonds were discovered in Brazil, and then in 1866 in South Africa, the main source of diamonds in the world today.
The idea that men should give diamonds to the women they 【C5】______is quite new. It was invented in the last century by De Beers, the company that owns the South African diamond mines. The idea that ’diamonds are forever’ does not hold water either. Although diamonds are very hard, they can be【C6】dam______.
The largest of all known diamonds was the Cullinan. It was【C7】disc______in South Africa in 1905 and given to Edward VII, king of Great Britain. It was cut into smaller stones, the largest of which—and still the largest cut diamond in 【C8】______(exist)—is called the Star of Africa.
There have been a lot of diamond thefts in recent years, but scientists can now mark stones to show who own them. Usually this mark is 【C9】______(visible), so thieves can’t tell if a diamond is marked. 【C10】O______the people who know how to make the mark appear can tell whether a diamond is marked or not. [br] 【C2】
选项
答案
unsure
解析
(该句的意思是“科学家仍然不确定钻石自然成形的准确过程,但可以确定的是钻石的成形需要高温和高压”,由后文的转折词but可知,空格处应填人否定形式。)
转载请注明原文地址:http://tihaiku.com/zcyy/3105797.html
相关试题推荐
[img]2016m12s/ct_eyyjsdm_eyyjsdreadb_0064_201612[/img]【B1】______Manyofthe
[img]2016m12s/ct_eyyjsdm_eyyjsdreadd_0076_201612[/img]Certainbirdsare,mo
[img]2016m12s/ct_eyyjsdm_eyyjsdreadd_0076_201612[/img]Certainbirdsare,mo
[img]2016m12s/ct_eyyjsdm_eyyjsdreadd_0076_201612[/img]Certainbirdsare,mo
[img]2016m12s/ct_eyyjsdm_eyyjsdreadd_0076_201612[/img]Certainbirdsare,mo
[img]2016m12s/ct_eyyjsdm_eyyjsdreadd_0076_201612[/img]Certainbirdsare,mo
WaterforLife[img]2016m12s/ct_eyyjsdm_eyyjsdcloze_
WaterforLife[img]2016m12s/ct_eyyjsdm_eyyjsdcloze_
WaterforLife[img]2016m12s/ct_eyyjsdm_eyyjsdcloze_
WaterforLife[img]2016m12s/ct_eyyjsdm_eyyjsdcloze_
随机试题
SevenTypesofEvidenceItisimportanttolearntouseeviden
Howmanypeoplewerekilledintheattack?[originaltext]Atleast30civiliansw
Kenya’sforeignministersaysheisleavinghispostbecauseof[originaltext]
Accordingtothelatestsurvey,GeorgeW.BushJr.doesn’thaveachancetowin
试述出版物保管养护的工作要求。
区分同质事物的差别依据是()A.事物的度 B.事物质的规定性 C.事物量的规
真人养脏汤的功用是A.温中祛寒,补益脾胃 B.温中补虚,降逆止呕 C.益气健
下列降血糖药中,必须注射给药才能起效的是A:胰岛素 B:格列美脲 C:阿卡波
长期备用隔离开关运行后应对其进行()红外测温。一次$;$二次$;$三次$;$四次
与高层和基层管理人员相比,中层管理人员更应具备的能力有()。A:目标设定能力
最新回复
(
0
)