Paragraph Demographic Change
1 By the end of the 1920s, American society had undergone a long and historic demographic change. Since the 1870s, the country had been moving from a more rural mode that was based on high birthrates-as high as 50 births annually per thousand people in the early nineteenth century-to a more metropolitan mode. Prior to the 1870s, the population of the country was increasing by about a third every decade; however, by the end of the 1920s, a radical about-face had taken place.
2 One major factor to affect the demographics of the country during this period was a dramatic decrease in birthrates. The trend during this era was more pronounced in urban areas but also had an effect in rural areas. As a result of the trend toward smaller families, particularly in cities, the birthrate was down to 27.7 births annually per thousand women by 1920 and had dropped even further-to 21.3 births annually per thousand women-by 1930.
3 At the same time, the deathrate, too, was falling. Urban living led to better sanitation, refrigeration, and water purification; it also resulted in better medical care as doctors and hospitals were more readily available. Most likely as a result of these factors, there were only eleven deaths per thousand annually by the early 1920s, which was half the rate of the 1880s.
5. Why does the author include the phrase as high as 50 births annually per thousand people in the early nineteenth century in paragraph 1?
(A) To show that metropolitan areas of the country had higher birthrates than rural areas
(B) To provide statistical evidence of the elevated birthrate in the 1870s
(C) To quantify what had happened with the American population in the previous century
(D) To argue against the belief that the demographics of the country had changed
6. The author uses the word however in paragraph 1 in order to
(A) to make it clear that an extreme change had taken place
(B) to emphasize how tremendously the population was increasing
(C) to point out an alternate explanation for the change
(D) to indicate a difference of opinion with other demographers
7. The author includes the word too in paragraph 3
(A) to indicate that both the birthrate and the deathrate were holding steady
(B) to show that the rural mode was similar to the metropolitan mode
(C) to clarify the explanation that population trends before and after 1870 were similar
(D) to emphasize that paragraph 3 discusses a second factor in the demographic change
8. Why does the author mention better medical care in paragraph 3?
(A) It helps to explain why the birthrate is increasing.
(B) It is an example of a factor that contributed to the improved birthrate.
(C) It helps to explain why the deathrate is increasing.
(D) It is an example of a factor that contributed to the improved deathrate.
9. The author includes the expression Most likely in paragraph 3 to show
(A) that the data about the average number of deaths was not verified
(B) that doctors and hospitals may not have actually been more available
(C) that other factors may have contributed to the decreasing deathrate
(D) that the deathrate may not have decreased as much as stated
正确答案：B_A_D_D_C
Paragraph Territoriality
1 In many species, members of the species exhibit aggressive behavior toward one another, often with a focus on territoriality, the fight for exclusive control of a particular area. The level of violence in territorial aggression varies widely from species to species, though few species fight other members of the species to death and instead rely on non-lethal contests for control of territory that involves noise-making maneuvers such as roaring or hissing or aggressive posturing or gestures.
2 Most bird species are known to be territorial to some degree, though the territorial behaviors exhibited by most species are limited to singing contests, which can go on for days, or threatening postures with wings lifted or extended. The swan, on the other hand, is quite unlike other birds in this respect. The swan may seem particularly elegant and serene as it glides across the surface of a lake; however, male swans are, in reality, quite territorial and will fight other male swans for the exclusive use of a lake no matter how large the lake is. Males will engage in ferocious contests, with their necks entwined as they attempt to cause mortal injury to each other.
15. Why does the author include the fight for exclusive control of a particular area in paragraph 1?
(A) It presents an argument against a previously stated point.
(B) It provides a definition of a previously stated term.
(C) It presents a second area of focus of aggressive behavior.
(D) It introduces a new idea to be further developed in the paragraph.
16. The author uses the word instead in paragraph 2 to show that the information that follows
(A) contradicts what precedes it
(B) expands upon what precedes it
(C) provides an example of what precedes it
(D) explains an effect of what precedes it
17. Why does the author mention singing contests in paragraph 2?
(A) To demonstrate that birds create beautiful sounds
(B) To provide an example of unusual behavior by birds
(C) To show how violently aggressive some bird behavior is
(D) To demonstrate that some types of territorial behaviors are not very aggressive
18. The author discusses the swan in paragraph 2 to provide an example of
(A) a bird that makes threatening postures with its wings
(B) a bird whose territorial behavior is extremely aggressive
(C) non-lethal contests for control of territory
(D) the limited aggressive behavior generally exhibited by birds
19. The author mentions their necks entwined in paragraph 2 in order
(A) to indicate that swans are really rather affectionate
(B) to emphasize how long swans' necks are
(C) to make the point that the swans are only pretending to hurt one another
(D) to create a mental image for the reader of fighting swans
正确答案：B_A_D_B_D
