篇一：普特英语听力 免费学习英语
What’s So Special About A Sharp Knife?
利刃特别在何处？
Everyone knows that a sharp knife cuts better than a dull one, but do you know why, exactly?
The purpose of the cutting edge of a knife is to concentrate the force that’s being applied at the handle.
When you push down on the handle of a knife you exert a force. The force on the handle and the edge are the same, but the areas in which the force is concentrated are quite different.
At the handle your hand’s force is spread over a wide area, but on the cutting edge it is concentrated in a very small area, so therefore the pressure on the edge is much greater.
You can easily see how this works with a piece of modeling clay, a nail with a wide head, and a nail with a small head. First hold the nail with the wide head by its shaft and push it head-first into the ball of clay. Then do the same with the small-headed nail.
The small-headed nail goes into the clay much more easily than the wide-headed nail. Since the head of the small nail has less surface area than the big one, the force of your push is concentrated in a smaller area, exerts more pressure on the clay, and so the nail goes in more easily. The same principal causes pointed high-heeled shoes to sink into a soft surface more easily than flat shoes.
By applying this principal to the knife you can see that with a keener edge there’s a greater concentration of the pressure on the edge, so it takes much less force to make the knife cut.
大家都知道锋利的刀刃的切割性能胜过钝刀，但您知道确切原因吗？
刀刃的作用就是把人们用在刀把上的力集中起来。
当你按下刀把时，你施加了一种力。这种力无论是在刀把还是刀刃上都是等量的，但力的聚集区域不同，所产生的效果十分迥异。
在你手中的刀把上，力会在一个较广阔的区域传播，但在刀刃上，力会聚集在一个非常小的区域，因此刀刃上的压力会剧增。
只要有一块橡皮泥、一枚宽头钉和一枚窄头钉，你很容易就能看到这一原理是如何运作的。首先将宽头钉的杆竖起，将其头朝下推入橡皮泥球。然后对窄头钉做同样动作。
窄头钉比宽头钉更容易嵌入橡皮泥。由于窄头钉的头部面积比宽头钉小，你的推力将集中在一个更小的区域，对橡皮泥产生更大的压力，因此钉子更容易嵌入。同理，尖高跟鞋比平跟鞋更易陷入表面柔软的物体。
将这一原理运用在刀上，你能看到，在锋利的刀刃上，压力能更好的聚集，因此切割起来更省力。
篇二：【整理】2008-02-25-1530 - Special 听力训练 - 普特英语听力论坛
【整理】2008-02-25-1530 - Special 听力训练 - 普特英语听力论坛 :::主攻英语听力训练的英语学习论坛 - Powered by Discuz!默认表情IPB表情酷猴呆呆男
diewupiaopiao我的帖子 空间 短消息 论坛任务个人中心 退出 论坛主站博客家园辞典问吧商城搜索QQ群帮助普特英语听力论坛 »
Special 听力训练 »
【整理】2008-02-25-1530最新经典佳句背诵！！！在线背单词新一代口语模仿训练系统上线！专治男女记不住单词的秘密[图]
在线词典和异地的TA一起来练口语吧！只要你有麦！普特新增在线听写复读系统！普特英语新一代口译训练系统上线！
返回列表 回复 发帖
发新话题[SE 1530 NEWS] 【整理】2008-02-25-1530qingchengshan 发短消息 加为好友
qingchengshan 当前离线
UID280235 帖子16665 积分35704 阅读权限100 来自sichuan 在线时间2554 小时 注册时间2005-10-11
最后登录2010-2-10
版主
UID280235 帖子16665 贡献值35704 普币3278 听力指数15991 阅读权限100 来自sichuan
在线时间2554 小时 注册时间2005-10-11 最后登录2010-2-10 1#
打印 字体大小: tT 发表于 2008-2-26 10:10 | 只看该作者 [SE 1530 NEWS]
【整理】2008-02-25-1530
SENEWS-2008-02-25-1530
【电信1】 RealVideo / mp3
【电信2】 RealVideo / mp3
【网通/教育网】 RealVideo / mp3
有疑难，请进-- 【1530News】--新闻突击队
版主提示:
一、若是自己的听写稿, 请发帖时标注'Homework'.
二、若是改稿, 请发帖时标注'on 某某人'并在修改处标红.
三、为了达到最快的下载速度,推荐使用迅雷高速下载本站音频/视频材料.
第十一期招收新学员报名正在进行中！！！
【整理】SENEWS-2008-02-25-1530
Special thanks to daiyuan1128, ambertsui, yzmin, hongqipiao and 依yiyi
It is 15:30 Universal Time. I'm Bob Doughty in Washington.
[1] Iraqi officials say at least 63 people have been killed in recent attacks against Shiite Muslims. Officials said the victims were traveling to the central city of Karbala for Arbaeen, one of Shiite Islam's holiest gatherings. At least four Shiites were killed in a bomb attack Monday in southern Baghdad. More than 15 others were reported wounded. On Sunday a bomber killed 56 Shiites who had stopped for a rest in Iskandariyah south of Baghdad. The United States military and American Embassy blamed al-Qaeda in Iraq supporters for that attack.
[2] A suicide bomber has killed Pakistan's top military medical officer. The Pakistani government says the Army's Surgeon General Lieutenant General Mushtaq Ahmed Baig died in the bombing Monday in Rawalpindi. It said the attack also killed his driver and at least five civilians. Twenty-five other people were reported wounded. This is the second time Pakistan's military has been attacked in
Rawalpindi this month. In early February a suicide bomber struck a military bus. Six people were killed and about 40 others hurt in that attack.
[3] Thousands of Palestinians have demonstrated in the Gaza Strip to protest Israel's blockade of the territory. Almost 5,000 adults and children held hands along a road between Rafah on Gaza's border with Egypt and Beit Hanun, in northern Gaza. Thousands of Israeli troops stood across the border to prevent any security violation. The demonstration ended without any violence. Israel says the blockade
is needed to pressure Hamas militants to stop their rocket attacks against Israel.
[4] The new president of South Korea is promising to increase wealth not only in his own country, but also in North Korea. Lee Myung-bak spoke at his swearing-in ceremony in Seoul Monday. Mr. Lee said his most important job is South Korea's economic recovery. He said South Korea is ready to help North Korea if it stops work on nuclear weapons and becomes a more open country. Mr. Lee also said the two Koreas could work on a new cooperative path if the North gives up its nuclear weapons. He said such cooperation could lead to large aid projects and international support. About 45,000 people attended the ceremony. Among them were Japanese Prime Minister Yasuo Fukuda and several other Asian leaders. American Secretary of State Condoleezza Rice represented the United States.
[5] American Defense Secretary Robert Gates is promising to help Indonesia improve its defenses. He says the United States is ready to help Indonesia reform its military. He spoke after meetings with the Indonesian president and defense minister Monday in Jakarta. Later Mr. Gates said he pressed for closer military ties between the two countries. Before arriving in Indonesia, the American defense secretary said it was important to improve relations with the Democratic Country. Indonesia has faced many attacks from Islamic militant groups, especially Jemaah Islamiah.
You are listening to the news in VOA Special English.
[ 本帖最后由 sfere 于 2008-2-27 11:10 编辑 ]
收藏 分享 评分
你的英语水平可以提高多少?
回复 引用 订阅 道具 TOP
daiyuan1128 发短消息
加为好友
daiyuan1128 当前离线
UID446834 帖子2 积分1 阅读权限10 性别男 来自北京 在线时间2 小时 注册时间2006-8-19 最后登录2008-6-26
普通百姓
UID446834 帖子2 贡献值1 普币1 听力指数1 阅读权限10 性别男 来自北京 在线时间2 小时 注册时间2006-8-19
最后登录2008-6-26 2#
发表于 2008-2-26 12:31 | 只看该作者 HW
It is 15:30 universal time; I am Bob Dowdy in Washington.
Iraqi officials say at least 63 people have been killed in recent attacks against Shiah Muslims. Official said the victims were
traveling to the central city of … for Albarin, one of Shiah Islam’s
holiest gatherings. At least 4 Shiahs were killed in a bomb attack one day … in Baghdad. More than 15 others were reported wounded. On Sunday a bomber killed 56 Shiahs who had stopped for a rest in …… south of Baghdad. The United States Military and American Embassy blamed …… supporters for that attack.
A suicide bomber has killed Pakistan’s top military medical officer. The Pakistani Government says the army’s Surgeon General, … General …… died in the bombing Monday in ……. It said the attack also killed his driver and at least 5 civilians. 25 other people were reported wounded. This is the second’s time Pakistan’s military has been attacked in …… this month. In early February a suicide bomber stroke a military bus. 6 people were killed and about 40 others hurt in that attack.
Thousands of Palestinians have demonstrated in the Gaza’s street to protest its reel’s blockade of the territory. Almost 5,000 adults and children held hands along the road between Raphar and Gaza’s border with Egypt and … in northern of Gaza. Thousands of Israel’s troops stood across the border to prevent any security violation. The demonstration ended without any violence. Israel says the
blockade is needed to pressure HAMAS militants to stop their rocket attacks against Israel.
The new President of South Korea is promising to increase wealth not only in his own country but also in North Korea. Lee Yongpark spoke at his swearing-in ceremony in Seoul Monday. Mr. Lee said his most important job is South Korea’s economic recovery. He said South Korea is ready to help North Korea, if it stops work on nuclear weapons and becomes a more open country. Mr. Lee also said the two Koreas could work on a new cooperative path if the North gives up its nuclear weapons. He said such cooperation could lead to large aid project and international support. About 45,000 people attended the ceremony. Among them were Japanese Prime Minister Yasuo Fukuda and several other Asian leaders. American Secretary of State
Condoleezza Rice represented the United States.
American Defensive Secretary Robert Gates is promising to help
Indonesia improve its defenses. He says:” the United States is ready to help Indonesia reform its military. He spoke after meetings with the Indonesian President and Defense Minister Monday in Jakarta. Later Mr. Gates said he pressed for closer military ties between the two countries. Before arriving in Indonesia, the American Defensive Secretary said it was important to improve relations with the democratic country. Indonesia has faced many attacks from Islamic militant groups, especially Gima Is lamia.
You are listening to the News in VOA Special English.
[ 本帖最后由 daiyuan1128 于 2008-2-26 12:34 编辑 ]
衣服下面的身体是神性，肉体之外的思想是自己
阶梯修改编辑太麻烦？用普特在线文本比较！
回复 引用 道具 TOP
ambertsui 发短消息
加为好友
ambertsui 当前离线
UID565883 帖子697 积分691 阅读权限90 性别女 来自GZ 在线时间4 小时 注册时间2007-4-3
最后登录2009-6-25
榜眼
UID565883 帖子697 贡献值691 普币1 听力指数17 阅读权限90 性别女 来自GZ 在线时间4 小时
注册时间2007-4-3 最后登录2009-6-25 3#
发表于 2008-2-26 13:29 | 只看该作者 Homework
It is 15:30 Universal Time. I’m Bob Doughty in Washington.
Iraqi officials say at least 63 people have been killed in recent attacks against Shiite Muslims. Officials said the victims were traveling to the central city of Karbala for Arbain, one of Shiite Islam’s holiest gatherings. At least four Shiites were killed in a bomb attack Monday in southern Baghdad. More than 15 others were reportedly wounded. On Sunday a bomber killed 56 Shiites who had stopped for a rest in Iskandariya, south of Baghdad. The United States’ military and American embassy blamed al-Qaeda in Iraq supporters for that attack.
篇三：我的英语听力[1][1]
《普特英语听力论坛论坛听写节目难度层次分级》出自：百味书屋
链接地址：http://www.850500.com/news/144598.html
转载请保留,谢谢!