cretaceous period

基本解释

The prints are believed to have been made during the Cretaceous period of the Mesozoic Era, Kim said in a statement.
這些足跡被認爲是在中生代白堊紀時期由儅時鳥類畱下的。
The temperature drop during the Cretaceous period would almost certainly have wiped out an 'abundance' of the world's dinosaurs.
曾經稱霸地球顯赫一時的恐龍，在白堊紀時代的這次溫度巨變中，似乎全都滅絕了。
The assembled family tree shows that lice started to radiate into new species well before the end of the Cretaceous period, Dr. Smith and his colleagues report in the current issue of Biology Letters.
史密斯博士和他同事在《生物學快報》上發文指出，建立起的系統樹表明在白堊紀末期之前虱子早就開始進化出不同的新物種。

These creatures lived more than sixty-five million years ago, during Earth's late Cretaceous period.
Scientists say it formed when high sea levels flooded the middle of North America, splitting the continent in two for millions of years during the late Cretaceous period.
The Tyrannosaurus lived in North America during the late Cretaceous Period.

My piece is set in the late Cretaceous period, 65 million years ago (give or take a few).
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