"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

That's what the optimist thinks-- not just for themselves individually, but for everybody, the total is always positive.

那是乐观主义者的想法-,而且不但是对他们自己，而是对所有人，等式结果总是正数。

耶鲁公开课 - 死亡课程节选