托福TPO68听力Lecture2原文+题目+答案+MP3音频下载

托福TPO68听力Lecture2原文+题目+答案+MP3音频下载

以下为托福TPO68听力Lecture2原文：

Listen to part of a lecture in a geology class.

Ok. As we said in the last class, the general consensus among scientists is that earth is 4.5 billion years old. So what was earth like when it was a new planet 4.5 billion years ago? Katie?

It was pretty much covered in magma with really fiery conditions like volcanoes. Plus, there were like giant rocks, media rights that collided with earth that would melt when they landed here.

Great. Melt or vaporize. This went on for hundreds of millions of years. There was no life here. Then just fire and molten rock. And no liquid water either know oceans. And when did things start to change?

It lasted about 500 million years, right ,until earth was like 500 million years old.

Okay. Researchers have deduced that since we don't have proof of any intact rocks from before then, that earth started cooling down after about 500 million years. Rocks earlier than that would have been obliterated by the fire and heat. Makes sense, right?

Sure.

So a few weeks ago we talked about Zircon. Anyone remember anything about Zircon?

It's a mineral. I know it has unusual properties, but....

。。。。。余下托福TPO68听力Lecture2原文省略！

托福TPO68听力Lecture2题目：

1.(单选题)

What is the lecture mainly about?

A.How researchers determine the rate at which Earth cooled

B.How climate change affected early life on Earth

C.Evidence that challenges a belief about the early conditions on Earth

D.Conflicting scientific hypotheses about the age of Earth

2.(单选题)

Prior to the 1980s researchers believed that Earth's climate was extremely hot during its first 500 million years What led researchers to this belief?

A.No undamaged rocks from that period had been found

B.Organisms from that period indicate that they survived extreme conditions.

C.Every mountain from that period had experienced intense volcanic activity.

D.Zircon crystals from that period contain evidence of hot conditions.

。。。。。余下托福TPO68听力Lecture2题目省略！

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