2、 How did Wignall calculate the killing power of those older volcanic eruptions?

A:By estimating how long they lasted.

B: By counting the dinosaurs they killed.

C: By studying the chemical composition of lava.

D:By comparing the proportion of life wiped out with the volume of lava produced.

本題正確答案為:D
本題解析:D 問題問的是：Wignall是如何計算出遠(yuǎn)古火上爆發(fā)的殺傷力的？答案在第二段。第二段有這樣一句話：He calculated the "killing efficiency" for these volcanoes by comparing the proportion of life they killed off with the volume of lava that they produced．他通過比較火山釋放出的熔巖的體積與殺死生命的比例計算這些火山的殺傷效力。
3、When did dinosaurs become extinct?

A:300 million years ago.

B:250 million years ago.

C:60 million years ago.

D:65 million years ago

本題正確答案為:D
本題解析:D 問題問的是：恐龍是什么時候滅絕的?答案在第三段。其中有這么一句話：He ignored the extinction which wiped out the dinosaurs 65 million years ago, because many scientists believe it was primarily caused by the impact of an asteroid．他沒有提及6千5百萬年前恐龍的滅絕是因為許多科學(xué)家相信恐龍的滅絕是受一顆小行星的影響。

4、What can be inferred from paragraph 3 concerning dinosaurs?www.zcyyw.com

A:They were killed off by an asteroid.

B:They died of drastic climate change.

C: They were wiped off by a volcanic eruption.

D:The cause of their extinction has remained a controversial issue.

本題正確答案為:D
本題解析:D 問題問的是：第三段還可以推導(dǎo)出有關(guān)恐龍的什么樣的信息?在討論第三題的答案時，我們已經(jīng)注意到了，Wignall沒有提6千5百萬年前恐龍的滅絕是否跟火山爆發(fā)有關(guān)是因為許多科學(xué)家相信恐龍的滅絕是受一顆小行星的影響。這就說明，關(guān)于恐龍滅絕的原因在科學(xué)家之間是有分歧的。

5、What is the main thesis of the article?

A: Volcanic eruptions are not always deadly.

B:Older volcanic eruptions were more destructive.

C:Carbon dioxide emissions often give rise to global warming.

D:It is not easy to calculate the killing power of a volcanic eruption.

本題正確答案為:B
本題解析:B 問題問的是：文章的主要論點是什么？答案在文章的第一句：Volcanoes were more destructive in ancient history, ．．．（古代火山更具破壞力）。