plastocene

例句：

1. 1. The plastocene era was characterized by the appearance of new species.
   白垩纪时期以新物种的出现为特征。
2. 2. The discovery of fossils in the plastocene layer has led to a better understanding of Earth's history.
   在白垩纪地层中发现的化石有助于更好地理解地球的历史。
3. 3. The plastocene period is often associated with the rise of mammals and the development of modern ecosystems.
   白垩纪时期通常与哺乳动物的兴起和现代生态系统的发展联系在一起。