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
名师推荐考前必看:六级高频词(11)
70个最值得关注的四六级听力备考词汇
四六级听力考试必背习语
六级阅读理解核心备考词汇归类一(A-C)
大学英语四六级单词最佳背诵法
名师总结四六级考试词汇(2)
提高效率背单词:选择适合自己的方法
08年12月六级考前测试:必备词汇(D)
六级阅读理解核心备考词汇归类三(I-P)
六级阅读考试核心高分词汇(D)
总结:四六级听力考试重点关注单词
六级阅读理解核心备考词汇归类二(D-H)
六级阅读考试核心高分词汇(U-W)
四六级高频词汇书真的有效吗
六级阅读考试核心高分词汇(R)
总结:四六级听力考试常考俗语
名师总结四六级考试词汇(1)
六级阅读考试核心高分词汇(T)
名师总结四六级考试词汇(5)
六级阅读考试核心高分词汇(A)
六级阅读考试核心高分词汇(I)
六级阅读考试核心高分词汇(F)
08年12月六级考前测试:必备词汇(N-O)
名师重点详解同根同缀词汇记忆法
四六级30个最经典的替换词
08年12月六级考前测试:必备词汇(I)
四六级写作中词汇量不足的应急措施
六级阅读考试核心高分词汇(S)
名师推荐考前必看:六级高频词(2)
英语四六级听力151组容易混淆拼错的单词
不限 |
英语教案 |
英语课件 |
英语试题 |
不限 |
不限 |
上册 |
下册 |
不限 |