Passage One
　　Questions 21 to 25 are based on the following passage.
　　What do Charles Darwin, Nicholas Copernicus and Frank J. Sulloway have in common?
　　The first two, of course, were revolutionary scientific thinkers: Copernicus established that the Earth revolves around the sun; Darwin discovered natural selection. And Sulloway? He’s a historian of science at Massachusetts Institute of Technology who has discovered something else these two men-and, indeed, most of the major pioneers in science over the last 400 years-have in common: they were, like Sulloway himself, preceded in birth by at least one other brother or sister. Birth order, he found, is the most reliable indicator of whether a scientist will embrace or attack radical new ideas.
　　The third of four children, Sulloway has spent 20 years searching out the birth order of 2,784 scientists who were on one side or the other of 28 scientific revolutions since the 16th century. He discovered that 23 of the 28 revolutions were led by later-borns.
　　Sulloway focused on the male-dominated world of science and the sole issue he measured was willingness to challenge established opinions. Those least likely to accept new theories were firstborns with younger brothers or sisters. The most radical were younger sons with at least one older brother.
　　According to Sulloway’s theory, firstborn children identify more readily with parental authority because, among other things, they are often put in charge of younger brothers or sisters.来源：www.examda.com
　　Through this identification, firstborns absorb the norms (规范,准则) and values of society in ways that subsequent children do not. The older child gets responsibility. They younger one tests the limits, tries to see what he can get away with.
　　21. What is the main idea of the passage?
　　A) Later-borns are more intelligent than firstborns.
　　B) Revolutionary thinkers tend to recognize the influence of birth order.
　　C) Major scientists always have something in common in their way of thinking.
　　D) One’s behaviour is often determined by birth order.
　　22. The historian of science mentioned in the passage is of the family.
　　A) the youngest child
　　B) neither the eldest nor the youngest child
　　C) the only child
　　D) the eldest child
　　23. The 2,784 scientists Sulloway studied ________.
　　A) had led 23 of the 28 scientific revolutions
　　B) were preceded in birth by at least one brother or sister
　　C) had either supported or opposed revolutionary ideas
　　D) had dominated the world of science for 400 years
　　24. According to Sulloway’s theory, who is most likely to challenge established ideas of science?
　　A) The only son with younger sisters.
　　B) Those who identify more readily with parental authority.
　　C) The only child of a family.
　　D) A person with at least one older brother or sister.
　　25. The author’s attitude towards Sulloway’s birth order theory is ________.
　　A) critical
　　B) defensive
　　C) neutral
　　D) inconsistent