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 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。