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 throughout the__1__available; it must therefore be kept in a closed container or held by a gravitational field, as in the__2__of a planets atmosphere. The distinction was a __3__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__4 __that the two phases are made up of different kinds of molecules. The theories now prevailing take a quite different approach by emphasizing what liquids and gases have in __5 __They are both forms of matter that have no __6 __structure, and they both flow readily.
The fundamental similarity of liquids and gases becomes clearly apparent when the temperature and pressure are __7__somewhat. Suppose a closed container __8__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 __9__to it. The combination of temperature and pressure at which the densities become __10__is called the critical point.
A. added B. case C. prominent D. held E. equal F. partially G. example H. previous I. space J. lifted K. permanent L. particularly M. extended N. raised O. common
答案:
I. I 2. B 3. C 4. D 5. O 6. K 7. N 8. F 9. A 10. E
如何让GRE词汇记忆更有效率?
GRE词汇背诵全程指导!
GRE词汇:每日十例句助你记单词(九)
GRE词汇易错部分总结(四)
GRE词汇记忆新方法(六)
GRE分类词汇分期大放送(3)
GRE词汇书选择优劣分析
GRE词汇:每日十例句助你记单词(一)
小心!美国生活处处是GRE词汇
GRE词汇:每日十例句助你记单词(六)
GRE词汇串讲:背诵单词
GRE词汇:每日十例句助你记单词(四)
GRE分类词汇分期大放送(5)
GRE词汇记忆新方法(四)
GRE词汇背诵 贵在坚持!
GRE词汇:读故事记忆单词
GRE分类词汇分期大放送(8)
GRE词汇:每日十例句助你记单词(五)
GRE“数量词与功能词”经典大发送
GRE词汇:每日十例句助你记单词(八)
GRE词汇背诵新思路
GRE单词背诵心态要放松
GRE词汇快速记忆法
GRE词汇记忆:警惕陷入三个记忆误区!
GRE词汇易错部分总结(二)
GRE词汇记忆新方法(一)
GRE词汇记忆新方法(五)
GRE词汇量“现状”描述
GRE词汇:“性价比”最高的记忆法
GRE词汇小科普(详解)
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |