Many theories have been put forward for the extinction of the dinosaurs, but most of them can be dismissed.
人们提出了许多关于恐龙灭绝的理论，但大多数都是不成立的。
Changes in climate before that period caused severe fluctuation in sea level, resulting in the extinction of the dinosaurs.
在此之前，气候的变化导致了海平面的剧烈波动，恐龙因此灭绝。
Some scientists hypothesize that the extinction of the dinosaurs resulted from the effects of an asteroid collision with Earth.
一些科学家假定，小行星撞击地球导致了恐龙的灭绝。
For instance, if it hadn't been for the extinction of the dinosaurs, we mammals would never have had an opportunity to flourish.
例如，如果没有恐龙的灭绝，我们这些哺乳动物就不会有机会繁荣昌盛。
Given how much ink has been spilled on the extinction of the dinosaurs, it's a wonder that even more hasn't been devoted to megatauna.
恐龙灭绝受到巨大关注，但却没有多少人关注巨型动物，这让人感到诧异。
The late Cretaceous extinction of the dinosaurs and ammonoids was just one of the more drastic in a whole series of such recurrent extinction episodes.
在这一系列周期性物种灭绝事件里，白垩纪晚期恐龙和菊石的灭绝仅仅是其中一个比较严重的事件。
Changes in climate before the Cretaceous period caused severe fluctuation in sea level, resulting in the extinction of the dinosaurs.
白垩纪以前的气候变化导致了海平面的剧烈波动，引发了恐龙的灭绝。
The extinction of the dinosaurs gave mammals their lucky break.
恐龙的灭绝则给了哺乳动物千载难逢的好机会。
The last big impact was 65 million years ago, and that led to the extinction of the dinosaurs.
最近一次大影响是65亿年前，导致了恐龙灭绝。
Dinosaurs' high level of fitness could also explain why mammals remained so small until the mass extinction of the dinosaurs 65 million years ago.
恐龙的高度适应性可能也解释了为什么哺乳动物的体型总是那么小，这种情况一直持续到六千五百万年前恐龙大规模灭绝。
An asteroid impact is famously responsible for the extinction of the dinosaurs 65 million years ago, but large comet impacts may be equally deadly.
众所周知，6千5百万年前一颗小行星的撞击导致了恐龙的灭绝，然而一颗大彗星的撞击可能是同样致命的。
Only after the mysterious mass extinction of the dinosaurs about 65 million years ago were our ancestors able to emerge into the daylight in any substantial Numbers.
只有在6500万年前，恐龙神秘地大规模灭绝后，我们的祖先才有可能大批出现在白天。
The November 26th issue of the journal Science included a study showing that the extinction of the dinosaurs some 65 million years ago allowed puny mammals to get really big.
11月26日发布的《自然》杂志里有一项研究表明，6千5百万年前恐龙的灭绝让弱小的哺乳类动物变得强大起来。
Interestingly, when the extinction of the dinosaurs, a group of animals lose their natural enemies, they slowly began to degenerate, the ultimate extinction or loss of the original survival ability.
有趣的是，当恐龙灭绝以后，一群动物失去了天敌，它们也慢慢开始退化，最终灭绝或丧失了原本的生存能力。
While there are a dozen or more mass extinctions in the geological record, the Cretaceous mass extinction has always intrigued paleontologists because it marks the end of the age of the dinosaurs.
虽然在地质记录中有十几次甚至更多的大灭绝，但白垩纪的大灭绝总是引起古生物学家的兴趣，因为它标志着恐龙时代的结束。
Presumably, those environmental disasters could have been responsible for the mass extinction, including the death of the dinosaurs.
据推测，这些环境灾难可能是物种大规模灭绝的成因，包括恐龙的灭绝。
The change in climate might be one of the causes for the extinction of dinosaurs.
气候的变化也许是恐龙灭绝的一个原因。
"We are currently witnessing the greatest extinction crisis since dinosaurs disappeared from our planet 65 million years ago," according to the International Union for Conservation of Nature.
“我们正在目击自六千五百万年前恐龙消失以来，这颗行星上最大规模的物种灭绝危机”，国际自然保护联盟声称。
One fragment of that ancient smash is thought to have struck Earth 65 million years ago, triggering a mass extinction that wiped out the dinosaurs.
据认为，那次古老冲撞的碎片在六千五百万年前曾经撞击地球，引发了消灭恐龙的大灭绝。
Instead of being driven to extinction by death from above, dinosaurs might have ultimately been doomed by death from below in the form of monumental volcanic eruptions.
最终有可能导致恐龙灭绝的原因很可能是猛烈的火山爆发，而不是以上导致恐龙灭绝的原因。
His movie of the extinction of dinosaurs was a great success.
他的关于恐龙灭绝的电影取得了巨大的成功。
Theories about the extinction of dinosaurs are still highly conjectural.
关于恐龙灭绝的理论仍然是带有很强的猜测性的。
With regard to the reasons for the extinction of dinosaurs, it is still being studied.
关于恐龙灭绝的原因，人们仍在不断地研究之中。
As for other reasons having led to the extinction of dinosaurs, scientists have pointed out the sudden increased volcanic activities might also be the reason having led to the extinction of dinosaurs.
至于其他有关导致恐龙灭绝的原因，科学家们指出，火山活动的突然加剧可能也是导致恐龙灭绝的原因。
However, recently, the material from the huge meteorite crashed in Mexico's Yucatan Peninsula has shown that it is not the reason having led to the extinction of dinosaurs.
不过，不久前有材料显示，坠落在墨西哥尤卡坦半岛的巨大陨石并非导致恐龙灭绝的原因。
Research scientists have shown the meteorite hit the earth about 30 million years earlier than the mass extinction of dinosaurs.
科学家们的研究表明，这颗陨石撞上地球的时间要比恐龙大规模灭绝的时间早大约30万年。
If this conclusion is confirmed, then the earlier theory that the meteorite led to the extinction of dinosaurs may be negative.
如果这一结论获得证实，那么此前有关陨石导致恐龙灭绝的理论可能就会被否定。
The mass extinction of terrestrial dinosaurs is the most important evolutionary event across the Cretaceous-Paleogene boundary.
陆生恐龙的绝灭是白垩系-古近系界线事件中最引人注目的。
The mass extinction of terrestrial dinosaurs is the most important evolutionary event across the Cretaceous-Paleogene boundary.
陆生恐龙的绝灭是白垩系-古近系界线事件中最引人注目的。
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