geologic epoch的用法和样例：
例句
- The quaternary period of geologic time extends from the end of the tertiary period to the present.
地质时期中的第四纪是从第三纪一直到现在。 - Although magnetic reversals have occurred many times in the geologic past, it is not yet possible to predict when the next reversal will occur.
尽管在过去地质时期地磁场发生了多次倒转，但要预测下次倒转将在何时发生也还是不可能的。
