[解析]
(1)C.主旨大意题.根据全文和第一段的"Scientists recently discovered that pictures on cave walls at Creswell Crags are the oldest known in Great Britain."可知,本文主要讲述 Cave art为什么是英国最古老的艺术,文章的后半部分给出了证据.故选C.
(2)A.细节理解题.根据文章的第二段"Archaeologists often date cave art with a process called radiocarbon dating."判断,考古学家可以计算出山洞艺术的日期.故选A.
(3)D.细节理解题.根据文章第四段的句子"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."可知,考古学家是根据两点判断Cave art的历史的:一些画被石笋覆盖着,而根据研究石笋已有12,800年的历史.故选D.
(4)C.细节理解题.根据短文的最后一句"It tells scientists that the Creswell Crags artists must have had a close connection to peoples several thousand kilometers away﹣another important clue to understanding how humans spread out across the world."可知,通过研究山洞艺术科学家了解了人类在世界上是怎么分布的.故选C.