They've lived through the K-T extinction.

它们经历了 K-T 大灭绝。

But does the K-T boundary really signify the absolute end of all dinosaurs?

不过KT界限层真的标志着所有恐龙的彻底消亡吗？

It needed to be the right size to be linked to the K-T boundary evidence.

要与KT界限层的证据连接起来，它的大小必须合适。

The most recent K-T extinction wiped out the dinosaurs 65 million years ago.

最近的 K-T 灭绝在 6500 万年前消灭了恐龙。

Cretaceous–Tertiary (K–T) extinction - For number one, we’re stepping as far back in time as we can.

第三纪 ( K- T) 灭绝— 白垩纪-— 第一， 我们尽可能地回到过去。

So then we have the AA as in BAT vowel, k, t, and then an unstressed syllable 'Ly' exact, Exactly.

因此，我们有 AA 如 BAT 元音，k，t，然后是一个非重读音节“Ly”，确切地说。

The reason why an asteroid was looked at as the cause of the Iridium spike at the K-T boundary, is because asteroids have an enormous amount of Iridium in them.

一颗小行星被看做是引起KT界限层铱猛增的原因，是因为小行星中有相当多的铱。

To be precise, we will be going back 66 million years ago to an event known as The Cretaceous–Paleogene extinction event, which is also known as the Cretaceous–Tertiary or K–T extinction.

准确地说， 我们将回到 6600 万年前的白垩纪-古近纪灭绝事件，也称为白垩纪-第三纪或 K-T 灭绝事件。