閱讀難度：

America's most popular teacher doesn't work at Harvard University or a fancy prep school. In fact, he doesn't work in a school at all, but his lessons have been viewed more than 56 million times, US News and World Report reports.

Salman Khan, a former hedge fund manager, is the founder of Khan Academy, a free online learning platform with a library of more than 2,300 videos covering everything from basic algebra and differential equations to the Vietnam War.

Most videos are brief – anywhere from a couple of minutes to a half hour, depending on the subject.

Khan scrawls equations and writes down key terms on a computer program that simulates a chalk board as he explains them with a voiceover track.

（點擊《美國新聞與世界報道》網(wǎng)站查看原文）

美國數(shù)學的救世主

?????? 《美國新聞與世界報道》消息，美國現(xiàn)在最受歡迎的老師已經(jīng)吸引了56萬人次觀看他的課程——他不是哈佛大學的老師，也并非來自知名補習學校，事實上，他根本就沒有在學校工作過。

?????? 薩爾曼?汗曾經(jīng)是一名對沖基金經(jīng)理，他創(chuàng)辦了免費教育網(wǎng)站“汗學院”。迄今為止，汗學院網(wǎng)絡平臺上的視頻數(shù)量超過2300段，從小學的簡單加法、大學微積分到講解越南戰(zhàn)爭，內(nèi)容非常廣泛。

?????? 大部分視頻都簡單易懂，因為科目的不同，視頻長度從幾分鐘到半小時不等。

?????? 汗在計算機上模擬建一個黑板，在上面寫方程式和畫草圖，另外還配有畫外音，對一些概念進行講解。

(China.org.cn June 15, 2011)