speak of 在这句话中怎么翻译，tpo阅读里面的一句话

qhdjessicaUID: 3642816

Runoff channels on Mars speak of a time 4 billion years ago (the age of the Martian highlands), when the atmosphere was thicker, the surface warmer, and liquid water widespread.

speak of 可以翻译成存在？该怎么正确理解speak of的正确意思呢？

qhdjessicaUID: 3642816

a time four years ago (the age of the Martian highlands) 火星高地的年龄不是一段时间吗， ago表示的是时间点吧？

gterlannUID: 3595027

speak of意思比较灵活，这里大概就是talk about的意思，我没看原文，估计是的；

ago是时间点，但是age对应的是four billion years而不是a time。