Proterozoic
n. 元古代, 元古代岩\\na. 元古代的, 元古代岩的
🗣️ 情景例句
I'm taking 19 credit hours.
我修了十九个学分。
Health does not consist with intemperance.
健康和放纵，彼此不相容。
when a significant number of people are living permanently in space.
如果有相当数量的人永久性地住在太空，