元古界

The Proterozoic eon is the most recent division of the geologic timescale.
从地质时间尺度来看，元古代是最近的一个分期。
Many of the earliest known fossils date from the Proterozoic era.
许多已知最古老的化石都来自元古代。
The Proterozoic is divided into three eras: the Paleoproterozoic, Mesoproterozoic, and Neoproterozoic.
元古代分为三个纪：古元古代、中元古代和新元古代。
During the Proterozoic, the Earth's atmosphere began to resemble its current composition.
在元古代期间，地球的大气层开始与现在的成分相似。
The Proterozoic saw the rise of the first complex life forms on Earth.
在元古代，地球上出现了第一种复杂的生命形式。
Geological events during the Proterozoic include the formation of supercontinents like Rodinia and Pannotia.
元古代的地质事件包括罗迪尼亚和潘诺西亚等超级大陆的形成。
The Proterozoic is characterized by the presence of abundant oxygen in the atmosphere.
元古代的特点是在大气中有大量氧气存在。
The Proterozoic eon spans approximately 2.5 billion years, from about 2.5 billion years ago to 541 million years ago.
元古代持续了大约25亿年，从大约25亿年前到5.41亿年前。
The Proterozoic is also significant for the development of plate tectonics on Earth.
元古代对于地球板块构造的发展也具有重要意义。
The Proterozoic is often referred to as the "Boring Billion" because it was a time of little change in the fossil record.
元古代通常被称为“乏味十亿年”，因为这段时间在化石记录中几乎没有变化。