Chronolith
[地质]岩石年代单位
🗣️ 情景例句
Great! Let's do it!
好。 我们去。
Knowledge advances by steps and not by leaps.
知识只能循序渐进，不能跃进。
I agree. Which museum would you like to visit?
我同意。你想参观哪个博物馆呢？