首页
登录
职称英语
Not many of the elements occur in nature as pure substances, lying around wa
Not many of the elements occur in nature as pure substances, lying around wa
游客
2024-02-29
20
管理
问题
Not many of the elements occur in nature as pure substances, lying around waiting for someone to pick them up. A few do, and it is not surprising that these were known and collected for various uses in societies around the globe as far back as several thousand years B. C. Sulfur is one of those elements. It was known to burn with smelly results and have an odd appearance. Its use was probably confined to religious ceremonies. Carbon was also known since antiquity, because the charred (烧焦的) bones of animals and portions of partially burned trees consist largely of carbon in the form of charcoal. Although we don’t know all the uses primitive peoples made of charcoal, we do know that it was the key to releasing many other elements from their chemical combination in rocks. For example, if a copper-containing rock was heated in a hot fire with charcoal present, the carbon in the charcoal would combine with the other elements in the rock, leaving free metallic copper. In ways like this people were able to discover the elements copper, iron, lead, tin, and zinc, although they didn’t necessarily appreciate that these substances were elementary. They just knew that they were useful
Iron also arrived occasionally from the heavens in the form of iron-containing meteorites (陨石). Because of this, one might think that iron would have been thought of as a "heavenly" element, a gift from the gods. Instead, this honor has always fallen to the element gold. Gold doesn’t fall from the skies, but it is found in its pure state in some places. It has the unusual property of never tarnishing (锈蚀) like other metals do. Gold objects don’t rust, as iron does, nor do they turn green or black on the surface as do many other metals.
The ancient Egyptians used gold for jewelry and for coins. Gold is still used for jewelry, although pure gold is too soft for this purpose. Coins and jewelry, instead, are made of alloys. These are metals made by melting two or more metals in a pot together in such a way that they dissolve in one another. Gold coins are usually 90 per cent copper. An alloy of gold and silver is called white gold. [br] Which of the following statements about gold is NOT true?
选项
A、It doesn’t fall from tile skies.
B、It doesn’t rust or tarnish.
C、It is used for jewelry.
D、Pure gold is optimal material for jewelry.
答案
D
解析
该题也是判断题,但问的是有关黄金的四句表述中哪一句不正确。源信息在第二段和第三段,文中将黄金和其它金属作了比较。第三段的第二句“Gold is still used for jewelry, although pure gold is too soft for this purpose”说明纯金不宜用来制作首饰。故选D)。
转载请注明原文地址:https://tihaiku.com/zcyy/3491850.html
相关试题推荐
Ihavecertainlyseenlotsofchangesinmylifetime!Ilookaroundmyhomeand
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
ASenseofCrisisAroundtheworld,governmentsseeviole
[originaltext]M:Ican’tbelieveyou’restilldrivingaroundinthispieceofj
[originaltext]M:Ican’tbelieveyou’restilldrivingaroundinthispieceofj
随机试题
[originaltext]PROFESSOR:Comeinandsitdown,Louise...Stuart.Isupposeyou’r
Thefirstwaywecanapproachlanguageisasaphenomenonoftheindividual
企业不再符合相应建筑业企业资质标准要求条件的,()入民政府住房城乡建设主管部门
经济订货批量模型(EOQ)的一个特点是:()A.相对来说对错误不敏感 B.
竣工验收的组织者是:A.施工单位 B.建设单位 C.设计单位 D.质检单位
男,39岁,上腹胀及不规律隐痛半年,胃镜检查见胃窦黏膜红白相间,以红为主,可见明
患者,男,48岁。支气管肺癌。病理诊断为“鳞状细胞癌”。 患者进行肺癌切除术后
企业以银行存款偿还债务,表现为()。 A.一项资产增加,另一项资产减少B
保险业监督管理的原则是()。A.以我为主、安全可控 B.优势互补、合作
肺炎链球菌肺炎引起缺氧的主要原因是A.气道阻力增加 B.PaCO升高 C.病
最新回复
(
0
)