Sifting meticulously, the volunteers collected every last tooth and vertebra and chip of bone — everything that had been overlooked by previous diggers. The work took three years. When finished they found that they had more than tripled the global total of dinosaur fossils from the late Cretaceous. The survey established that dinosaurs remained numerous right up to the time of the KT impact. "There is no reason to believe that the dinosaurs were dying out gradually during the last three million years of the Cretaceous," Sheehan reported.
志愿者们精心筛选，捡起了剩下的每一颗牙齿、每一根脊骨和每一片骨头——反正是以前的发掘者留下的一切东西。这项工作花了三年时间。当工作结束的时候，他们发现自己已经——为这颗行星——把白垩纪末期的恐龙化石增加了两倍多。这次调查确认，到发生KT撞击事件的时候，恐龙的数量还相当多。“没有理由认为。在白垩纪的最后300万年里恐龙在渐渐消失。”希恩在报告里说。

We are so used to the notion of our own inevitability as life's dominant species that it is hard to grasp that we are here only because of timely extraterrestrial bangs and other random flukes. The one thing we have in common with all other living things is that for nearly four billion years our ancestors have managed to slip through a series of closing doors every time we needed them to. Stephen Jay Gould expressed it succinctly in a well-known line: "Humans are here today because our particular line never fractured — never once at any of the billion points that could have erased us from history."
我们习惯于认为，我们自己成为生命的主导物种是不可避免的，因此无法理解我们之所以在这里，仅仅是因为来自天外的撞击发生得合时以及其他无意中的侥幸事儿。我们与其他生物只有一个共同点，那就是，在将近40亿年时间里，在每个必须的时刻，我们的祖先成功地从一系列快要关上的门里钻了进去。斯蒂芬·杰伊·古尔德有句名言，简要地表达了这个意思：“今天人类之所以存在，是因为我们特定的家族从来没有中断过——在10亿个有可能把我们从历史上抹掉的关键时刻一次也没有中断过。”
We started this chapter with three points: Life wants to be; life doesn't always want to be much; life from time to time goes extinct. To this we may add a fourth: Life goes on. And often, as we shall see, it goes on in ways that are decidedly amazing.
我们在本章开头部分提出了三点：生命想存在；生命并不总是想大有作为；生命不时灭绝。我们也许可以再加上一点：生命在前进。我们将会看到，生命往往以极其令人吃惊的方式前进着。