By the end of this year,截止今年年底，there&#39ll be nearly a billion people on this planet这个星球上将有接近十亿人口that actively use social networking sites.在很活跃地使用社交网站。The one thing that all of them have in common他们有一个共同点，is that they&#39re going to die.就是他们终将死去。While that might be a somewhat morbid thought,也许这是个有点病

Ted英语演讲：挑战病魔：尼古拉斯:社交网络是怎样预测流行病的传播