"Even an optimist like Frank Drake estimates that there would be no more than about in the galaxy, which means that the nearest one is likely to be about 1,000 light years away."

VOA: standard.2010.04.16

No, OK and that's correct, because each photon of light actually has more energy than is needed to eject an electron.

没有，好，对了，因为每一个光子实际上,都有更多的能量去逐出一个电子。

麻省理工公开课 - 化学原理课程节选

The big question for American now is whether there will be light at the end of the tunnel after more than 8 years of war there, after all that life lost and fouture spent.

现在对于美国一个重要的问题就是,是否有曙光的出现,8年的战争中，美国政府花费了大量的金钱，很多人也因为战争也失去了生命。

普林斯顿公开课 - 国际座谈会课程节选