TOEFL模擬試題
Questions 12-20
The elements other than hydrogen and helium exist In suchsmall quantities that it is accurate to say that the universesomewhat more than 25 percent helium by weight andsomewhat less than 25 percent hydrogen.
Astronomers have measured the abundance of heliumthroughout our galaxy and in other galaxies as well. Helium hasbeen found In old stars, in relatively young ones, in interstellar gas, and in the distant objectsknown as quasars. Helium nuclei have also been found to be constituents of cosmic rays that fallon the earth (cosmic "rays" are not really a form of radiation; they consist of rapidly movingparticles of numerous different kinds). It doesn't seem to make very much difference where thehelium is found. Its relative abundance never seems to vary much. In some places, there may beslightly more of it; In others, slightly less, but the ratio of helium to hydrogen nuclei always remainsabout the same.
Helium is created in stars. In fact, nuclear reactions that convert hydrogen to helium areresponsible for most of the energy that stars produce. However, the amount of helium that couldhave been produced in this manner can be calculated, and it turns out to be no more than a fewpercent. The universe has not existed long enough for this figure to he significantly greater.Consequently, if the universe is somewhat more than 25 percent helium now, then it must havebeen about 25 percent helium at a time near the beginning..
However, when the universe was less than one minute old, no helium could have existed.Calculations indicate that before this time temperatures were too high and particles of matter weremoving around much too rapidly. It was only after the one-minute point that helium could exist.By this time, the univ
erse had cooled sufficiently that neutrons and protons could stick together. But the nuclear reactions that led to the formation of helium went on for only a relatively short time. By the time the universe was a few minutes old, helium production had effectively ceased.
12. what does the passage mainly explain?
(A)How stars produce energy
(B)The difference between helium and hydrogen
(C)When most of the helium in the universe was formed
(D)Why hydrogen is abundant
13. According to the passage, helium is
(A) the second-most abundant element in the universe
(B) difficult to detect
(C) the oldest element in the universe
(D) the most prevalent element in quasars
14. The word "constituents" in line 7 is closest in meaning to
(A) relatives
(B) causes
(C)components
(D) targets
15. Why does the author mention "cosmic rays't' in line 7?
(A)As part of a list of things containing helium
(B) As an example of an unsolved astronomical puzzle
(C) To explain how the universe began
(D) To explain the abundance of hydrogen in the universe
16. The word "vary" in line 10 is closest ill meaning to
(A) mean
(B) stretch
(C) change
(D) include
17. The creation of helium within stars
(A) cannot be measured
(B) produces energy
(C) produces hydrogen as a by-product
(D) causes helium to be much more abundant In old stars than In young star:
18. The word "calculated" in line 15 is closest in meaning to
(A) ignored
(B) converted
(C) increased
(D) determined
19. Most of the helium in the universe was formed
(A) in interstellar space
(B) in a very short time
(C) during the first minute of the universe's existence
(D) before most of the hydrogen
20. The word "ceased" in line 26 is closest in meaning to
(A)extended
(B)performed
(C)taken hold
(D)stopped
Questions 21-30
In colonial America, people generally covered their beds with decorative quilts resembling thoseof the lands from which the quitters had come. Wealthy and socially prominent settlers made quiltsof the English type, cut from large lengths of cloth of the same color and texture rather thanstitched together from smaller pieces. They mad these until the advent of the Revolutionary Warin I 775, when everything English came to be frowned upon.
Among the whole-cloth quilts made by these wealthy settlers during the early period are
those now called linsey-woolseys. This term was usually applied to a fabric of wool and linen used In heavy clothing and quilted petticoats worn in the wintertime. Despite the name, linsey-woolsey bedcovers didnot often contain linen. Rather, they were made of a lop layer of woolen or glazed worsted wool fabric, consisting of smooth, compact yarn from long wool fiber dyed dark blue, green, or brown with a bottom layer of a coarser woolen material, either natural or a shade of yellow. The filling was a soft layer of wool which had been cleaned and separated and the three layers were held together with decorative stitching done with homespun linen thread. Later, cotton thread WM used for this purpose. The design of the stitching was often a simple one composed of interlocking circles or crossed diagonal lines giving a diamond pattern.
This type of heavy, warm, quilted bedcover was so large that it hung to the floor. The corners are cut out at the foot of the cover so that the quilt fit snugly around the tall four-poster, beds of the 1700's, which differed from those of today in that they were shorter and wider; they were short because people slept in a semi-sitting position with many bolsters or pillows, and wide, because each bed often slept three or more. The linsey-woolsey covering was found in the colder regions of the country because of the warmth it afforded. There was no central heating and most bedrooms did not have fireplaces.
21. What does this passage mainly discuss?
(A) The processing of wool
(B) Linsey-woolsey bedcovers
(C) Sleeping habits of colonial Americans
(D) Quilts made in England
22. The word "prominent" in line 3 is closest in meaning to
(A) isolated
(B) concerned
(C) generous
(D) distinguished
23. The author mention the Revolutionary War as a time period when
(A) quills were supplied to the army
(B) more immigrants arrived from England
(C) quills imported from England became harder to find
(D) people's attitudes toward England changed.
24. The phrase "applied to" in line 8 is closest in meaning 10
(A) sewn onto
(B) compared to
(C) used for
(D) written down on
25. The term "linsey-woolsey" originally meant fabric used primarily in
(A)quilts
(B)sheets
(C)clothing
(D) pillows
26. The word "coarser" in line 13 is closest in meaning to
(A)older
(B)less heavy
(C)more attractive
(D)rougher
27. The quilts described in the second and third paragraphs were made primarily of
(A) wool
(B) linen
(C) cotton
(D) a mixture of fabrics
28. It can be inferred from the third paragraph that the sleeping habits of most Americans have changed since the 1700's in all the following ways EXCEPT
(A) the position in which people sleep
(A) the numbers of bolsters or pillows people sleep on
(C) the length of time people sleep
(D) the number of people who sleep in one bed
29. The word "afforded" in line 24 is closest in meaning to
(A) provided
(B) spent
(C) avoided
(D) absorbed
30. Which of the following was most likely to be found in a bedroom in the colder areas of the American colonies?
(A)A linsey-woolsey
(B)A vent from a central healing system
(C) A fireplace
(D) A wood stove
Questions 31-40
Growing tightly packed together and collectively weaving a dense canopy of branches, astand of red alder trees can totally dominate a site to the exclusion of almost everything else.Certain species such as salmonberry and sword ferns have Line adapted to the limited sunlightdappling through the canopy, but few evergreen trees (S) will survive there; still fewer cancompete with the early prodigious growth of alders. A Douglas fir tree reaches its maximum rate ofgrowth ten years later than an alder, and if the two of them begin life at the same time, the alderquickly outgrows and dominates the Douglas fir. After an alder canopy has closed, the Douglas firsuffers a marked decrease in growth, often dying within seven years. Even more shade-tolerantspecies of trees such as hemlock may remain badly suppressed beneath aggressive young alders.
Companies engaged in intensive timber cropping naturally take a dim view of alderssuppressing more valuable evergreen trees. But times are changing; a new generation of forestersseems better prepared to Include in their management plans consideration of the vital ecologicalrole alders, play.
Among the alder's valuable ecological contributions is its capacity to fix nitrogen in nitrogen-deficient soils. Alder roots contain clusters of nitrogen-fixing nodules like those found on legumessuch as beans. in addition, newly developing soils exposed by recent glacier retreat and plantedwith alders show that these trees are applying the equivalent of ten bags of high-nitrogen fertilizerto each hectare per year. Other chemical changes to soil i
n which they are growing Include a lowering of the base content and rise In soil acidity, as well as a substantial addition of carbon and calcium. to the soil,
Another important role many alders play in the wild, particularly in mountainous areas, is to check the rush of water during spring melt. In Japan and elsewhere, the trees are planted to stabilize soil on steep mountain slopes. Similarly, alders have been planted to stabilize and rehabilitate waste material left over from old mines, flood deposits, and landslide areas in both Europe and Asia.
31. What does the passage mainly discuss?
(A)Differences between alder trees and Douglas fir trees
(B)Alder trees as a source of timber
(C)Management plans for using alder trees to improve soil
(D)The relation of alder trees to their forest environments
32. The word "dense" in line I is closest in meaning to
(A) dark
(B) tall
(C) thick
(D) broad
33. Alder trees can suppress the growth of nearby trees by depriving them of
(A) nitrogen
(B) sunlight
(C) soil nutrients
(D) water
34. Thc passage suggests that Douglas fir trees are
(A)a type of alder
(B)a type of evergreen
(C)similar to sword ferns
(D)fast-growing trees
35. It can be inferred from paragraph I that hemlock trees
(A) are similar in size to alder trees.
(B) interfere with the growth of Douglas fir trees
(C) reduce the number of alder trees In the forest
(D) need less sunlight than do Douglas fir trees
36. It can be inferred from paragraph 2 that previous generations of foresters
(A) did not study the effects of alders on forests
(B) did not want alders In forests
(C) harvested alders for lumber
(D) used alders to control the growth of evergreens
37. The word "they" in line 21 refers to
(A) newly developing soils
(B) alders
(C) bags
(D) chemical changes
38. According to the passage that alders are used in mountainous areas to
(A) nitrogen
(B) calcium
(C) carbon
(D) oxygen
39. It can be Inferred from the passage that alders are used in mountainous areas to
(A) prevent water from carrying away soil
(B) hold the snow
(C) protect mines
(D) provide material for housing
40. What is the author's main purpose in the passage?
(A) To argue that alder trees are useful in forest management
(B) To explain the life cycle of alder trees
(C) To criticize the way alders take over and eliminate forests
(D) To illustrate how alder trees control soil erosion
Questions 41-50
In taking ups new life across the Atlantic, the early European settlers of the United States did not abandon the diversions with which their ancestors had traditionally relieved the tedium of life. Neither the harshness of existence on the new continent nor Line the scattered population nor the disapproval of the clergy discouraged the majority from the pursuit of pleasure.
City and country dwellers. of course. conducted this pursuit in different ways. Farm dwellers in their isolation not only found it harder to locate companions in play but also thanks to the unending demands and pressures of their work, felt it necessary to combine fun with purpose. No other set of colonists too soseriously one expression of the period. "Leisure Is time for doing something useful." in the countryside farmers therefore relieved the burden of the daily routine with such relaxation as hunting. fishing, and trapping. When a neighbor needed help, families rallied from miles around to assist In building a house or barn, husking corn, shearing sheep. or chopping wood. Food, drink, and celebration after the group work provided relaxation and soothed weary muscles.
The most eagerly anticipated social events were the rural fairs, Hundreds of men, women, and children attended from far and near. The men bought or traded farm animals and acquired needed merchandise while the women displayed food prepared in their kitchens, and everyone, Including the youngsters, watched or participated in a variety of competitive sports, with prizes awarded to the winners. These events typically included horse races, wrestling matches, and foot races, as well as some nonathletic events such as whistling competitions. No other occasions did so much to relieve the isolation of farm existence.
With the open countryside everywhere at hand, city dwellers naturally shared in some of the rural diversions. Favored recreations included fishing, hunting1 skating, and swimming. But city dwellers also developed other pleasures. which only compact communities made possible.
41. What is the passage mainly about?
(A) Methods of farming used by early settlers of the United States
(B) Hardships faced by the early settlers of the United States
(C) Methods of buying, selling, and trading used by early settlers of the United States
(D) Ways in which early sett
lers of the United States relaxed
42. What can be inferred about the diversions of the early settlers of the United States?
(A) They followed a pattern begun in Europe.
(B) They were enjoyed more frequently than in Europe.
(C) The clergy organized them.
(D) Only the wealthy participated in them.
43. Which of 'he following can be said about the country dwellers' attitude toward "the pursuit of pleasure"?
(A) They felt that it should help keep their minds on their work.
(B) They felt that it was not necessary.
(C) They felt that it should be. productive.
(D) They felt that it should not involve eating and drinking.
44. The phrase "thanks to" in line 8 is closest in meaning to
(A)grateful for
(B) help with
(C) because of
(D) machines for
45. The word "their" in line B refers to
(A) ways
(B) farm dwellers
(C) demands
(D) pressures
46. What is meant by the phrase "double-purpose" in line 11 ?
(A) Very frequent
(B) Useful and enjoyable
(C) Extremely necessary
(D) Positive and negative
47. The phrase "eagerly anticipated" in line 16 is closest in meaning to
(A) well organized
(B) old-fashioned
(C) strongly opposed
(D) looked forward to
48. Which of the following can be said about the rural diversions mentioned in the last paragraph in which city dwellers also participated?
(A) They were useful to the rural community.
(B) They involved the purchase items useful in the home.
(C) They were activities that could be done equally easily in the towns
(D) They were all outdoor activities.
49. What will the author probably discuss in the paragraph following this passage?
(A) The rural diversions enjoyed by both urban and rural people
(B) Leisure activities of city dwellers
(C) Building methods of the early settlers in rural areas
(D)Changes in the lifestyles of settlers' as they moved to the cities
50.Where in the passage does the author mention factors that might prevent people from enjoying themselves?
(A) Lines 3-5
(B) Lines 12-14
(C) Lines 17-20
(D)Lines 25-27
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