6和18

18和24

35和84．

文明在传承与交流中发展。

材料一：凡一代有一代之文学，楚之骚，汉之赋，六代之骈语，唐之诗，宋之词，元之曲，皆所谓一代之文学，而后世莫能继焉者也。此可谓一代有一代之文学。——王国维《宋元戏曲史》

材料二：人文主义者从古希腊、古罗马文化中发现了以人为本、勇于追求、乐观向上的精神；又从《圣经》里找到了早期基督教的理想：人们不分种族、无论贵贱，在上帝面前一律平等……——张跃发主编《近代文明史》

材料三：中国古代有“秀才不出门，便知天下事”的说法，今天这种说法已经通过计算机网络变成了现实。人们可以在网上浏览新闻、查询各种各样的信息资料，进入浩瀚的知识海洋；迅速的电子邮件可以把信件在几秒种之内传到千里之外，并能在屏幕上做长时间的通话，……互联网……越来越多的人感受到它给我们生活带来的实实在在的变化。——人民教育出版社《中国历史》（八年级下册）

    We live in computer age (时代). People1 scientists, teachers, writers and even students use computers to do all kinds of work. But more than 30 years ago, 2couldn't do much. They were very big and expensive. Very 3people were interested in them and knew how to use them. Today computers are smaller and 4. But they can do a lot of work, many people like to use them. Some people 5have them at home. Computers become very important because they can work 6than people and make fewer mistakes. Computers can 7people do a lot of work. Writers now use computers to   8. Teachers use them to help teaching. Students use them to   9. Computers can also remember what you   10them. Computers are very useful and helpful. They are our friends. Do you want to have a computer?

如图，一只蚂蚁从点A沿圆柱表面爬到点B，如果圆柱的高为8cm，圆柱的底面半径为$\frac{6}{\mathrm{\pi }}$cm，那么最短的路线长是（　　）