In the early 1960s Wilt Chamberlain was one of only three players in the National Basketball Association (NBA) listed at over seven feet. If he had played last season, however, he would have been one of 42. The bodies playing major professional sports have changed dramatically over the years, and managers have been more than willing to adjust team uniforms to fit the growing numbers of bigger, longer frames.
The trend in sports, though, may be obscuring an unrecognized reality：Americans have generally stopped growing. Though typically about two inches taller now than 140 years ago, today's people—especially those born to families who have lived in the U.S. for many generations—apparently reached their limit in the early 1960s. And they aren't likely to get any taller. "In the general population today, at this genetic, environmental level, we've pretty much gone as far as we can go," says anthropologist William Cameron Chumlea of Wright State University. In the case of NBA players, their increase in height appears to result from the increasingly common practice of recruiting players from all over the world.
Growth, which rarely continues beyond the age of 20, demands calories and nutrients—notably, protein—to feed expanding tissues. At the start of the 20th century, under-nutrition and childhood infections got in the way. But as diet and health improved, children and adolescents have, on average, increased in height by about an inch and a half every 20 years, a pattern known as the secular trend in height. Yet according to the Centers for Disease Control and Prevention, average height—5′9〞for men, 5′4〞for women—hasn't really changed since 1960.
Genetically speaking, there are advantages to avoiding substantial height. During childbirth, larger babies have more difficulty passing through the birth canal. Moreover, even though humans have been upright for millions of years, our feet and back continue to struggle with bipedal posture and cannot easily withstand repeated strain imposed by oversize limbs. "There are some real constraints that are set by the genetic architecture of the individual organism," says anthropologist William Leonard of Northwestern University.
Genetic maximums can change, but don't expect this to happen soon. Claire C.Gordon, senior anthropologist at the Army Research Center in Natick, Mass. , ensures that 90 percent of the uniforms and workstations fit recruits without alteration. She says that, unlike those for basketball, the length of military uniforms has not changed for some time. And if you need to predict human height in the near future to design a piece of equipment, Gordon says that by and large, "you could use today's data and feel fairly confident."
1.Wilt Chamberlain is cited as an example to______.
A.illustrate the change of height of NBA players
B.show the popularity of NBA players in the U.S.
C.compare different generations of NBA players
D.assess the achievements of famous NBA players
2.Which of the following plays a key role in body growth according to the passage？
A.Genetic modification. B.Natural environment.
C.Living standards. D.Daily exercise.
3.On which of the following statements would the author most probably agree？
A.Non-Americans add to the average height of the nation.
B.Human height is conditioned by the upright posture.
C.Americans are the tallest on average in the world.
D.Larger babies tend to become taller in adulthood.
4.We learn from the last paragraph that in the near future______.
A.the garment industry will reconsider the uniform size
B.the design of military uniforms will remain unchanged
C.genetic testing will be employed in selecting sportsmen
D.the existing data of human height will still be applicable
5.The passage intends to tell us that______.
A.the change of human height follows a cyclic pattern
B.human height is becoming even more predictable
C.Americans have reached their genetic growth limit
D.the genetic pattern of Americans has altered
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1.【答案】A。
【解析】第一段在提到NBA球員張伯倫（Chamberlain）身高超過七英尺后，又講到“The bodies playing major professional sports have changed dramatically over the year”，因而引用張伯倫的例子主要說明的是NBA球員身高的變化。故正確答案為A。
2.【答案】C。
【解析】文章第二段中提到“In the general population today, at this genetic, environmental level, we've pretty much gone as far as we can go”，第三段中提到“But as diet and health improved, children and adolescents have, on average, increased in height by about an inch and a half every 20 years”。說明生活水平在成長中占據(jù)了主要角色，A選項中modification以及B、D選項在文中都沒有提到。故正確答案為C。
3.【答案】B。
【解析】A、C選項本身有錯誤，可以排除；D選項在文中沒有提到，利用排除得到正確答案為 B。故正確答案為B。
4.【答案】D。
【解析】由最后一段的最后一句話，“...you could use today's data...”，可知D選項符合題意。故正確答案為D。
5.【答案】C。
【解析】全文由NBA球員張伯倫引出美國人身高的變化，但實際上“...apparently reached their limit in the early 1960s.”（參看第二段），后面又講到了這種沖突的原因。主要內(nèi)容還是在強調(diào)后者，即從基因上講，美國人的身高已經(jīng)達到了極限。故正確答案為C。
