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
考研
【F1】Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use
【F1】Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use
admin
2017-10-23
29
问题
【F1】
Petroleum is the largest source of liquid fuel, and, in spite of attempts to develop synthetic fuels, and the continued use of solid fuels, world consumption of petroleum products is about four times greater now than in 1940.
Crude petroleum oil from different oilfields is never exactly identical in composition. Although all petroleum is composed essentially of a number of hydrocarbons, they are present in varying proportions in each deposit, and the properties of each deposit have to be evaluated.【F2】
Samples are subjected to a series of tests in the laboratory, the object of which is largely to determine the correct processing methods to be adopted in each case.
Petroleum is not normally used today in the crude state.【F3】
The mixture of oils of which it is composed must be separated out into a number of products such as petrol, aviation spirit, kerosene, diesel oils and lubricants, all of which have special purpose.
The main method of separation used, in refineries is fractional distillation, although further processing is normally required to produce marketable petroleum products. The different hydrocarbons present in petroleum have different boiling temperatures, and the fractions can therefore be isolated according to their boiling temperatures. Petrol, for instance, is a mixture of the lower-boiling hydrocarbons, with boiling temperatures ranging from 100℃ to 400℃. Diesel oils on the other hand have boiling temperatures of upwards of 400℃.
【F4】
Distillation was originally carried out in batch—stills and, although this is still done for special purposes, the development of the pipe—still has revolutionized refinery processes, since it allows continuous vaporization and rectification of the fractions.
The pipe-still consists of a bricok-lined furnace, in which is fitted a battery of tubes, through which the crude oil is pumped. The oil is heated, and petrol vaporization occurs. The oil then enters the fractionating tower, where it is distilled by coming into contact with condensed vapor which has previously been evolved from the still. Fractions of different boiling ranges are drawn off at different points in the tower, or, in some plants, in a series of towers, each one distilling successively heavier fractions.
【F5】
The heavier distillates, such as gas oil, undergo various other processes, of which the most important is known as cracking.
In this process, they are heated to a temperature of about 550℃, as a result of which the heavier molecules are broken up, lighter oils such as petrol being produced. Catalytic cracking, in which silicon compounds are used as catalysts to aid the process of decomposition, gives higher octane petrols. These are widely used as motorcar fuels, since the high octane value reduces the tendency of the fuel to detonation.
【F2】
选项
答案
油样被送进化验室进行一系列化验,其目的在很大程度上决定了每一个样品应采取的正确提取方法。
解析
这是一个含有非限定性定语从句的主从复合句。主句中的谓语动词be subjected to暗含被动,在翻译为汉语时可以不转化为主动形式,沿用句子的形式。非限定性定语从句中的先行词the object所指“油样被送进化验室进行化验的目标”。而其后的被动语态结构to be adopted…无法猜测这一动作的施动者,因此应采取主动的翻译方法。sample“标本,样品,采样,抽取……的样品”。
转载请注明原文地址:https://jikaoti.com/ti/sok7FFFM
0
考研英语一
相关试题推荐
Intheidealizedversionofhowscienceisdone,factsabouttheworldarewaitingtobeobservedandcollectedbyobjectiveres
Inthefollowingtext,somesentenceshavebeenremoved.ForQuestions1-5,choosethemostsuitableonefromthelistA-Gtofi
Inthefollowingtext,somesentenceshavebeenremoved.ForQuestions1-5,choosethemostsuitableonefromthelistA-Gtofi
Inthefollowingtext,somesentenceshavebeenremoved.ForQuestions1-5,choosethemostsuitableonefromthelistA-Gtofi
Overthepastcentury,allkindsofunfairnessanddiscriminationhavebeencondemnedormadeillegal.Butoneinsidiousformco
Upuntilafewdecadesago,ourvisionsofthefuturewerelargely—thoughbynomeansuniformly—glowinglypositive.Scienceand
By1830theformerSpanishandPortuguesecolonieshadbecomeindependentnations.Theroughly20million【C1】______ofthesenati
By1830theformerSpanishandPortuguesecolonieshadbecomeindependentnations.Theroughly20million【C1】______ofthesenati
In1924America’sNationalResearchCouncilsenttwoengineerstosuperviseaseriesofexperimentsatatelephone-partsfactory
Writingforanhistoricalseriesistricky,andtheoutcomeisnotalwaysasuccess.ThebestoverallEuropeanhistoryinEnglis
随机试题
企业所得税纳税人的各项存货的发生和领用,其实际成本的计价方法有,()。
乙公司现有生产线已满负荷运转,鉴于其产品在市场上供不应求,公司准备购置一条生产线.公司及生产线的相关资料如下:材料一:乙公司生产线的购置有两个方案可供选择;A方案生产线的购买成本为7200万元,预计使用6年,采用直线法计提折旧,预计净
下列各项中,不属于速动资产的是()。
在采购与付款循环中,属于不相容职务的有()。
关于期权,下列说法正确的是()
男同学小陈平时自由散漫,学习不认真,一天在课堂上用手机给班上的女同学发短信“曾某,我爱你”,被上课的王老师发现收缴,并将小陈的短信向全班同学宣读,同时指责其“思想堕落,道德败坏”。下课后小陈要求王老师归还手机,王老师说:这是罪证不能归还,要交学校教育处。校
邓小平同志提出现代化建设的战略重点有三点,放在第一位的是()。
某二叉树中有n个叶子结点,则该二叉树中度为2的结点数为()。
SELLINGTACTICSNOTESBusinessPresentationPayAttentiontoGettingAttention1Amajorobstacleofsellingthingsisthatyou
WhenTVnewsprogramsreportwarsordisasters,theeditorsrarelyusethemosthorrifyingpicturesofdeadorwoundedvictimsb
最新回复
(
0
)