●首页 加入收藏 网站地图 热点专题 网站搜索 [RSS订阅] [WAP访问]  
语言选择:
英语联盟 | www.enun.cn
英语学习 | 英语阅读 | 英语写作 | 英语听力 | 英语语法 | 综合口语 | 考试大全 | 英语四六 | 英语课堂 | 广播英语 | 行业英语 | 出国留学
品牌英语 | 实用英语 | 英文歌曲 | 影视英语 | 幽默笑话 | 英语游戏 | 儿童英语 | 英语翻译 | 英语讲演 | 求职简历 | 奥运英语 | 英文祝福
背景:#EDF0F5 #FAFBE6 #FFF2E2 #FDE6E0 #F3FFE1 #DAFAF3 #EAEAEF 默认  
阅读内容

2017职称英语考前每日一练[理工类第13期-C级][1]

[日期:2014-04-01]   [字体: ]
第6部分:完形填空(第51~65题,每题1分,共15分)

  阅读下面的短文,文中有15处空白,每处空白给出4个选项,请根据短文的内容从4个选项中选择1个最佳答案,涂在答题卡相应的位置上。

The Development of Rubber

  Here is the story of rubber. From the earliest time it was common knowledge _______(51) the Peruvians that when a cut was made in the outside skin of a rubber tree, a white liquid _______(52) milk came out, and that _______(53) this a sticky (粘的) mass of rubber might be made. This rubber is soft when warm, so that it is possible to give it any _______(54). The Peruvians made the_______(55) that it was very good for keeping out the wet. Then in the early 1800's, the Americans made use of it for the-first time. First they made overshoes to_______(56) their feet dry. Then came a certain Mr. Mackintosh, who made coats of cloth covered with natural rubber. From that day to this we have been coating cloth with rubber as Mr. Mackintosh _______(57), and our raincoats are still named after him.

  But these first rubber overshoes and raincoats were all soft and sticky in summer, and_______(58) and inelastic (无弹性的) in the winter when it was cold. But the rubber we have today is soft and elastic (有弹性的),_______(59) very strong m even in the warmest summer and the coldest winter. This was made_______(60) by a man called Goodyear. After many_______(61), he found that nitric acid (硝酸) made the rubber much better, but it is not hard and strong enough. Then a strange thing took_______(62). A friend of his, Nicholas Hayward, had the idea in his sleep that rubber might be made hard and strong if mixed with sulfur (硫磺) and put in the sun. Goodyear put this idea_______(63) the test, and saw that it did have more or less the desired effect though somewhat less than more. The only effect it had was on the outside of the rubber. It is common knowledge now that the_______(64) to make rubber hard and strong is by heating it with sulfur. It took Goodyear four more years to find this method. When at last he did it, he had_______(65) at all. Everythin

123下一页  GO
   免责声明:本站信息仅供参考,版权和著作权归原作者所有! 如果您(作者)发现侵犯您的权益,请与我们联系:QQ-362192,本站将立即删除!
 
阅读:

推荐 】 【 打印
相关新闻      
本文评论       全部评论
发表评论

点评: 字数
姓名:
内容查询

热门专题
 图片新闻