A
Scientists recently discovered that pictures on cave walls at Creswell Crags are the oldest known in Great Britain.But they didn't find out in the usual way.
Archaeologists often date cave art with a process called radiocarbon dating.The technique can measure the age of carbon found in charcoal (木炭) drawings or painted pictures.Carbon is an element found in many things，including charcoal and even people.But in this case，there was no paint or charcoal to test.People carved the pictures of animals and figures into the rock using stone tools.The scientists had an “aha！” moment when they noticed small rocks stuck to the top of the drawings.The small rocks must have formed after the drawings were made.
“It is rare to be able to scientifically date rock art，” said Alistair Pike，an archaeological scientist at Britain's University of Bristol.“We were very fortunate that some of them were covered by stalagmites (石笋)．”
When a test proved that the stalagmites formed 12，800 years ago，the scientists knew the art underneath them had to be at least that old.And some of the animals shown，like the European bison，are now extinct—another tipoff that the art is quite old.
The artists came to Creswell Crags.This place is one of the farthest points north reached by our ancient ancestors during the Ice Age.At that time，much of the North Sea was dry，so people could move about more easily.
Some tools and bones found there are 13，000 to 15，000 years old.They show that the travellers hunted horses，reindeer，and arctic hare.Their artwork is similar to art in France and Germany.It tells scientists that the Creswell Crags artists must have had a close connection to the people several thousand kilometres away—another important clue to understanding how humans spread out across the world.
【语篇解读】 本文是一篇说明文。科学家们最近发现了英国最古老的壁画，并试图推测它们的年代、主题等。
1．The underlined word “Archaeologists” in Paragraph 2 probably refers to people ．
A．who study things left behind by people in the past
B．who have rich experience in painting
C．who are interested in wild animals
D．who are good at using stone tools
A [词义猜测题。文章的第二段对archaeologists的工作内容做了描述：用放射性碳测定年代。据此可推知，其意思应是“考古学家”。]
2．Why do scientists say the art is quite old?
A．The animals carved in the stone are strange.
B．The art was carved into stone with stone tools.
C．The cave is one of the farthest point in the world.
D．Some pictures were covered by stalagmites more than 10，000 years old.
D [推理判断题。根据第三、四段可知，一些画表面覆盖着的石笋已有12 800年的历史，据此科学家推测出此画非常古老。]
3．What can we learn from the passage?
A．Carbon is a rare element.
B．To date rock art in scientific methods is not very difficult.
C．Some animals shown on the cave walls at Creswell Crags have died out.
D．During the Ice Age，it was more difficult for people to travel around by land than by sea.
C [细节理解题。由第四段第二句可知，岩石壁画里的某些动物，如欧洲野牛已经灭绝，所以C项正确。]
4．Which of the following would be the best title for the passage?
A．Cave Art in Britain
B．Cave Art Found in an Unusual Way
C．Cave Art Proved to Be Britain's Oldest
D．Cave Art About Animals Is Most Beautiful
C [标题归纳题。本文主要讲述了已知的英国最古老的壁画，内容包括年代的推测，壁画的主题、特点及其意义等，所以选C项。]
