基本解释adj.白垩的；白垩纪的n.白垩纪；白垩系同根派生 英汉例句用作形容词 (adj.)The story takes place 6500 years ago in the late Cretaceous period.故事发生在6500万年前的白垩纪晚期。用作名词 (n.)From the Cretaceous, Tarim basin began the new evolutional stage of foreland basin.从白垩纪初期开始