(2018·山东省威海市二模)Big cats have existed on the earth for millions of years，though scientists aren't sure exactly how long.But a new study indicates that a skull(颅骨)of a snow leopard(豹)relative that was recently unearthed is 4.4 million years old.That makes it the oldest big cat fossil(化石)ever found.
A team of US and Chinese scientists unearthed the skull in Tibet.This creature is not a direct ancestor to big cats，but it is closely related to the snow leopard，study leader Jack Tseng told the Associated Press.The fossil lends evidence to the belief that big cats existed in Asia and spread out from there.
Big cats are at the top of the food chain and have few predators of their own.Big cats include snow leopards，clouded leopards，tigers and lions.Based on genetic judgements，most scientists believe they first existed in Central Asia.But previously，the oldest known big cat fossil was 3.6 million years old and found in Africa.
The new fossil findings were published in the November 13 issue of the science journal Proceedings of the Royal Society B：Biological Sciences.Tseng and his team were fossil hunting in the Himalayas in 2010 when they discovered some bones，including the buried cat skull.The researchers were able to determine its age by studying the surrounding rocks and soil.The skull indicates that the animal was about the size of a clouded leopard，which can grow up to 50 pounds.In 2012，the team returned to unearth more cat bones.
David Polly from Indiana University told the Associated Press that the fossil is “convincingly older than the_current_record_holder”．He added that there could be even older big cat fossils in the Tibetan platea to uncover.
【语篇解读】 本文讲述了最新考古发现——一个大型猫科动物的颅骨化石。
1．What does the newly unearthed skull prove?
A．Big cats might have their origins in Asia.
B．The oldest fossil is 4.4 million years old.
C．The snow leopard is the oldest big cat.
D．The skull is of big cats' direct ancestor.
【答案】 A 推理判断题。由第二段最后一句话“The fossil lends evidence to the belief that big cats existed in Asia and spread out from there.”可推知，该化石使我们相信大型猫科动物起源于亚洲，然后繁衍到其他地方。
2．What does the underlined word in Paragraph 3 mean?
A．relatives. B．enemies.
C．partners. D．protectors
【答案】 B 猜测词义题。所在句意为“大型猫科动物位于食物链的顶端，所以几乎没有天敌”。
3．How do the researchers know the skull's age?
A．By measuring its size and forehead.
B．By examining other bones around it.
C．By studying its chemical composition.
D．By exploring the rocks and soil around it.
【答案】 D 细节理解题。由第四段第三句话“The researchers were able to determine its age by studying the surrounding rocks and soil.”可知，通过研究化石周围的岩石和土壤来测量化石的年代。
4．Where was “the current record holder”in the last paragraph found?
A．Asia. B．Africa.
C．America. D．Australia.
【答案】 B 推理判断题。画线词意为“现在的纪录保持者”，应该指的是新化石发现之前的最古老的化石；而第三段最后一句话“But previously，the oldest known big cat fossil was 3.6 million years old and found in Africa.”可知，它是在非洲发现的。
