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 11 available; it must therefore be kept in a closed container or held by a gravitational field, as in the 12 of a planets atmosphere. The distinction was a 13 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 14 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 15 They are both forms of matter that have no 16 structure, and they both flow readily. The fundamental similarity of liquids and gases becomes clearly apparent when the temperature and pressure are 17 somewhat. Suppose a closed container 18 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 19 to it. The combination of temperature and pressure at which the densities become 20is 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. particularlyM. extended N. raised 0. common II. I 12. B 13. C 14. D 15. O 16. K 17. N 18. F 19. A 20. E
UN female, New flag and Apollo 11 倡议提名女秘书长,新西兰换国旗和阿波罗11号再创历史
Indian state introduces 'fat tax' 印度一省拟征收“脂肪税”
Zika virus and the A4 waist challenge 寨卡病毒,“A4腰挑战”
Cyclists make Olympic history, 400-year-old shark 英国自行车运动员创英奥运历史,400岁格陵兰鲨鱼
India's sewer workers and British school standards 印度下水道工人施工安全,英国在校生学习成绩下降
Mars bars and baby gorilla 火星巧克力棒和大猩猩产幼子
Brexit and Hockney's art 英国脱欧公投后进展,大卫·霍克尼艺术展
The cost of protecting the environment, Juno space probe 保护环境付出的代价,“朱诺”木星探测器
Ditch 和 abandon 之间的区别
Alligator takes boy and Tate Modern extension 鳄鱼拖走小男孩,泰特现代美术馆扩建完工
IOC on Russian doping and hot June 奥委会就涉俄兴奋剂事件报告进展,六月高温破纪录
Art and football 海底发现文物,莱斯特城足球俱乐部曼谷庆功
US-Cuba flights and male cosmetic surgery 美国-古巴复航和男性整容手术
Counting elephants, Australian Elvis 空中数大象,澳大利亚“猫王节”
Phelps makes history and marine species 菲尔普斯创造历史,海洋新物种
Battery risk, Farmer anti-theft solution 纽扣电池的潜在危险,牧场主防盗有术
Angelina Jolie to divorce, Karaoke star at 80 安吉丽娜·朱莉提出离婚申请,八十岁老人出唱片
Big Ben and gorilla surprise 维修大本钟,大猩猩生子
Distinguished 和 distinguishable 之间的区别
In one ear and out the other 左耳进,右耳出
Ebola outbreak and brain injuries 埃博拉疫情,脑部创伤
Dangerous heartbeat, Spike Lee and the Oscars 危险的心跳,斯派克·李抵制奥斯卡
Delhi's pollution and South Africa's solar power 新德里环境污染,南非发展太阳能
Simple, innocent, naive, pure 四个近义词的区别
Zuma in court and stressed horses 南非总统受审和马的精神压力
Ten a penny 多得遍地都是
Diabetes warning and Queen at 90 糖尿病激增引忧, 英国女王90岁生日
All things to all people 八面玲珑
Connection and link 两个表示“关系”的单词
Antibiotics and escalator etiquette 美国人过多使用抗生素,伦敦地铁扶梯礼仪
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