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
The difference between a liquid and a gas is obvious under the conditions of temperature and pressure commonly found at the surf
The difference between a liquid and a gas is obvious under the conditions of temperature and pressure commonly found at the surf
admin
2009-10-15
127
问题
The difference between a liquid and a gas is obvious under the conditions of temperature and pressure commonly found at the surface of the Earth. A liquid can be kept in an open container and fill it to the level of a free surface. A gas forms no free surface but tends to diffuse(扩散)throughout the space available; it must therefore be kept in a closed container or held by a gravitational field, as in the case of a planet’s atmosphere. The distinction was a prominent feature of early theories describing the phases of matter. In the nineteenth century, for example, one theory maintained that a liquid could be" dissolved" in a vapor without losing its identity, and another theory that held the two phases are made up of different kinds of molecules. liquids and gases. The theories now prevailing take a quite different approach by emphasizing what liquids and gases have in common. They are both forms of matter that have no permanent structure, and they both flow readily. They are fluids.
The fundamental similarity of liquids and gases becomes clearly apparent when the temperature and pressure are raised somewhat. Suppose a closed container partially filled with a liquid is heated. The liquid expands, or in other words becomes less dense; some of it evaporates. In contrast, the vapor above the liquid surface becomes denser as the evaporated molecules are added to it. The combination of temperature and press at which the densities become equal is called the critical point. Above the critical point the liquid and the gas can no longer be distinguished; there is a single, undifferentiated fluid phase of uniform density.
选项
A、The Properities of Gases and Liquids.
B、What Fluids and Gases Are Made of.
C、New Uses for the Gas and the Liquid.
D、New Theories about Fluids and Gases.
答案
A
解析
从文章内容分析,第一段主要讲了气体与液体的不同之处,第二自然段着重说明两者的相同之处,都是在说明气体与液体的性质。故应选A。也可用排除法,得此答案。
转载请注明原文地址:https://kaotiyun.com/show/Hb5d777K
本试题收录于:
公共英语二级笔试题库公共英语(PETS)分类
0
公共英语二级笔试
公共英语(PETS)
相关试题推荐
【B1】【B18】
Co-oprationmeans______.Cropscanbeproducedindesertonlybecause______.
Theyoungmanwenttoatown______.Whentheyoungmanplayedajokeonhim,theservantwasnotangrybutsmiledbecause____
TheZipCode,thenumericalsystem,waspublicizedin______.TheseconddigitintheZipCodeidentifies______.
AWoman’sFriendship,ananalyticalportrayalofsocialandsexualrelationships,makesironiccommentonasectionofAustralia
Thegroupofboyshadtostopbecause______.Theplanesucceededincarryingtheboyonboardwith______intheair.
Accordingtothepassage,notmanyanimalshave.Thesuccessorfailureofacoconuttrapdependson______.
Onedayamangaveanad.inmostofthenewspapersinEngland,sayingthathehimselfwasayoungmanofmillionsofpoundsand
Laser-doppleradar______.WhichofthefollowingstatementsisNOTtrueaccordingtothepassage______.
随机试题
公共关系
不良反应发生率最高的药物是
不属于经济全球化的表现的是( )。
投保人变更受益人未经被保险人同意,人民法院应认定变更行为无效。()
下图为一幅书法作品,对其书体判断正确的()。
尽管在最近的选举调查中,所有的被调查者回答说:“他们分别忠于两个主要政党的其中之一。”但是在这两个主要政党的每个政党中有过三分之一的选民说,他们对这两个主要政党的施政纲领已不再着迷,如果有第三个政党成立,他们将会加入这个党。然而,即使这个调查反映了全体选民
在二审程序中,对于()的情况,人民法院应作出维持原判。
从所给的四个选项中,选择最合适的一个填入问号处,使之呈现一定的规律性:
Scientistshavelongsoughttopreventsharpmemoriesfromdullingwithage,buttheproblemremainsstubborn.Nowresearchpu
有以下程序 main() {chars[]"Yes\n/No",*ps=s; puts(ps+4); *(ps+4)=0; puts(s); } 程序运行后的输出结果是(选项D中的第一行是空行)
最新回复
(
0
)