UNIT 9课时跟踪检测(三)语言技能应用练（word练习）-【新课程学案】新教材2023-2024学年高中英语选择性必修3 （北师大版）

UNIT 9课时跟踪检测(三)语言技能应用练 Ⅰ.阅读理解 A Scientists have solved a puzzle about modern humans, after research showed that a famous skull of a human ancestor found in South Africa is a million years older than experts thought.This discovery has changed what we know of human history. The skull, which scientists have named “Mrs Ples”， is from an ape-like human relative from a species called Australopithecus africanus (南方古猿非洲种). It was found near Johannesburg in 1947 and, based on evidence from its surroundings, it was thought to be between 2.1 and 2.6 million years old. This puzzled scientists, because although Mrs Ples looks like a possible early ancestor of early humans, the first true humans had already evolved by the time she apparently lived. For this reason, scientists decided that, Australopithecus afarensis (南方古猿阿法系), a similar species from Eastern Africa that lived about 3.85 and 2.95 million years ago, was our most likely ancestor instead. To get a more accurate age of Mrs Ples, a team led by Professor Darryl Granger of Purdue University in Indiana, used a new method to date the sandy rocks where the skull lay. They measured the amount of certain chemicals in rocks, which form at a steady rate when they are exposed to cosmic rays (宇宙射线) on Earth's surface. Once rocks are buried, these chemicals stop forming and slowly disappear; the surviving amount reveals how much time has passed since the rocks (or bones) were on the surface. The new study shows that Mrs Ples and other australopithecine bones nearby are between 3.4 and 3.7 million years old. This means they lived at the same time as their Eastern African relatives, so either group could have given rise to modern humans. However, team member Dr Laurent Bruxelles pointed out that over millions of years, at only 2,500 miles away, these groups had plenty of time to travel and to breed with each other. In other words, the groups could quite easily have met, had children together and both been part of the history of mod