How old is the earth? The ancient Babylonians（古巴比伦人） believed that the earth was 2 million years old. They were more correct than some people who lived much later.
     In 1650, an Irish archbishop（大主教） named James Ussher stated that the world was created at 9:00 a.m. on Sunday, October 23, in 4004 B.C.. Ussher based this date on his studies of the Bible and other ancient writings. His statement was printed in a number of books and was accepted by many other scholars（学者）.
     There were no geologists in Ussher’s time. It was only in the 1700s that people began to look carefully at the earth’s crust（地壳） and understand what they saw. They began to realize that whole mountain ranges had been worn down by wind and water. Deep valleys had been carved by running streams.
     By 1880, geologists were certain the earth’s surface had been greatly changed by slow forces. They estimated that the earth was probable more than 10 million years old. By 1900, geologists changed that figure to 100 million years. One person who helped change people’s ideas about the age of the earth was Charles Darwin. He proved that living creatures had changed, very slowly, over long periods of time.
     In modern times, new evidence （证据） has shown that the earth’s age must be measured in billions, rather than millions of years. Astronomers （天文学家）, comparing the earth to the sun and some stars, estimate that the earth is 4 to 5 billion years old. Today, most scientists accept this estimate.

1. The age of the earth must be measured in ____.
   A. hundreds of years                 B. thousands of years
   C. billions of years                     D. months and years
 2. The underlined word “estimated ” in paragraph 4 means ____.
   A. judged             B. calculated        
   C. measured        D. imagined
3. Charles Darwin changed people’s ideas ____.
   A. about the dates on the rocks        
   B. about how old they were
   C.about the age the earth           
   D. about the Irish archbishop
 4. While it is not directly stated, the article suggests that __________.
   A. there have always been geologist     
   B. scientists still learn about the earth
   C. Charles Darwin changed animals       
   D. estimating the age of the earth is not easy
5. Which of the following statements is NOT true?
   A. We do not have an exact date for the creation of the earth.
   B. There were no geologists in Ussher’s time.
   C. Scientists kept changing their estimates of the earth’s age.
   D. James Ussher was born on October 23 in 4004 B.C..

1. C  文章中谈到2 million years old， more than 10 million years old 和100 million years，但根据文章最后一节…, new evidence has shown that the earth’s age must be measured in billions, rather than millions of years.,可以确定此题的答案。
2. A  根据文章的上下文意思可以猜出此处的“estimated ”意为 判断，估计，评判， 故选 A。
3. C  从文章第四节One person who helped change people’s ideas about the age of the earth was Charles Darwin. 可以认定答案是C。
4. B  根据题干意思，文章中没有直接谈及，但给读者以暗示的是：科学家仍在进一步研究地球、了解地球。
5. D　文章第二节所讲的是…James Ussher 说the world was created at 9:00 a.m. on Sunday, October 23, in 4004 B.C.，而不是他出生于那日。