96年10月 托福聽力文字

1. I want to play tennis tomorrow but I didn't bring my racket with me this evening.
Do you have one I could borrow?
What does the man imply?

2. I thought this shirt was a great deal but I washed it once and it shrunk so much that I can't wear it.
Some bargain. You should ask for a refund.
What does the woman mean?

3. I broke my ankle last Tuesday. And now I have to be on crutches for six weeks.
I'm sorry to hear that. Is there anything I can do for you?
What does the woman mean?

4. Why didn't you call me last night like you were supposed to?
I did your time was busy.
What does the man mean?

5. Sue, would you like a sandwich or something?
Oh, please don't bother. I can get something later.
What does the woman mean?

6. This report is due tomorrow. Would you be able to work on it with me tonight?
Unfortunately I have another commitment.
What does the woman mean?

7. I wonder where the books I ordered are. I expected to receive the package several days ago.
Maybe you'd better check it with the company. They could be temporarily out of stock.
What does the man suggest the woman do?

8. I just have to type this last page and then I'm through.
By then I'll be done too.
What does the woman mean?

9. Did you read the editorial in the paper about the mayor's speech?
I sure did. But I think they twisted the meaning of what he said.
What does the man say of the editorial?

10. Why do we go to see a movie tonight? A good comedy might cheer you up.
I would. But I the reason that I've been so down is all this work I have to do.
What can be inferred about the man?

11. I'd like to try to sell some of my textbooks from the last semester.
You and a few hundred other people.
What does the woman imply?

12. Could I talk to you for a minute about the discrepancy I found in this graph?
I'm kind of in the middle of things right now.
What does the woman mean?

13. Do you know if George is coming to the meeting?
Oh, no. I was supposed to tell that he is sick and can't come.
What does the man mean?

14. Dick, please don't tie up the phone. I need to make a call.
I'll be off in a minute.
What will the man do?

15. Saliy says we should meet her in the park at noon.
I thought we were meeting at the library.
What do the speakers disagree about?

16. I'm sort of upset with my brother. He hasn't answer either of my letters.
Well, just remember how hectic your freshman year was.
Give him a chance to get settled.
What does the man imply?

17. I wonder what this new flavor of ice cream tastes like?
I tried it last week. If I were you, I would stick with an old favorite.
What can be inferred from the conversation?

18. Pete had hoped to have his apartment painted by this time.
But he hasn't started yet, has he?
What does the woman imply about Pete?

19. You don't believe in diet, do you?
There is nothing wrong with them but they have to combine with exercise to do any good.
What does the man mean?

20. I'm amazed that you still haven't gotten to know your neighbors.
They tend to keep to themselves.
What does the man mean?

21. Joe, could you please help me straighten the rug? I'll move it while you lift up this side of the desk.
Sure. Oh, just a minute. The lamp is still on it.
What will the man probably do next?

22. I had to stand in line at the bank for about half an hour. There were only two tellers open.
That's where you and I differ. I would've gone back another time.
What does the woman imply?

23. I was touched that our neighbor brought over a dish when we moved in.
Yeah. Mrs. Smith really goes out of her way for others.
What can be inferred about Mrs. Smith?

24. Where are you up to now?
To meet a friend to come in on the subway.
What does the woman mean?

25. My company is flying me out to Hawaii on business next week.
That's great. Where are they putting you up?
What does the man want to know?

26. It's good to see you, Mary. How have you been?
Actually I have been feeling under the weather recently.
What does the woman mean?

27. It's a really nice apartment. But the owners want two-month rent in advance and I just don't have it.
Do you think it would help if they knew what a good tenant you are? You could get your landlord to write them a letter.
What does the woman suggest the man do?

28. Good morning, East Coast Data Process. May I help you?
Caroline? Oh, dear, I'm sorry, I thought I dialed Jack Easton, your number must be just above his in my address book.
What can be inferred from the conversation?

29. There's a nonstop train for Washington leaving here at 2:15.
That will be faster than taking the one that leaves at 2:00 and it will give us time to get a bite to eat.
What does the woman imply?

30. Sorry about your report. I didn't realize it was in that stack of papers.
Don't worry about it. Luckily I saved a copy on my computer.
What can be inferred from the conversation?

PART B
31-34 Conversation between two students.
* Hi, Bob. How is your oral presentation coming along?
* What oral presentation? I don't have to give mine until the end of the next week.
* You mean you haven't even started working on it yet?
* No. I need the pressure of a deadline to get inspired.
* Gee. I'm just the opposite. I can't concentrate unless I know I have plenty of time. Besides I have a big physics test next week so I want to get my presentation out of the way.
* What's your presentation on?
* William Carlos Williams.
* Wasn't he a poet? I thought we were supposed to focus on a short story.
* He wrote short stories, do you know?
* Really? I never knew that I guess I'll learn more on Tuesday. Is that when you are supposed to talk?
* Uh-huh. But I was going to offer you sneak preview. I'm looking for someone to tell me whether I'm talking to fast and whether you can follow what I'm saying.
* I guess I could do that. When were you thinking of?
* Will tonight be all right? I have a last to go to now but I'll be around after dinner.
* That sounds good. I'll stop by your room. It's probably quieter there than in my hall.

31. What do the students mainly discuss?

32. What does the woman want the man to tell her?

33. What will the man probably do after dinner?

34. Where do the students arrange the meet?

35-37 Conversation between two students.
* Have you ever read anything about pseudo sciences?
* You mean fake sciences? Yes. In fact I was just reading some articles about the brain. I have been looking through some of my roommate's science magazines and I came across an article on phrenology.
* Phrenology, wasn't that the pseudo science founded by the scientist Franz Gall?
* Yes. Gall maintained that people's characters could be determined by the size and the shape of their skulls. For example he though that a pump in a certain place on the head means that the person had the ability of a musician.
* Really? I wonder what phrenologists would say about the bumps on my head. Would they say I have the abilities to be a doctor, or a plumber, or a thief.
* Well, I'm not sure exactly what the connection is between a person's abilities and the physical characteristics of the head. But although there's no scientific basis for phrenology, it is true that the bead is the center control for the rest of the body.
* I guess you are right. Scientists now know that different parts of the brain control different parts of the body.
* Yes. And I wouldn't be surprised that the scientists one day discover that certain aspect of phrenology has scientific application.

35. What is the source of the woman's information?

36. According to phrenology, what determines a person's character?

37. What does the woman say about the sections of the brain?
 
PART C
38 to 42 Talk given in a library science class.
In the early 1800s, the paper industry was still using rags as its basic source of fiber as it had for many centuries. However the rag supply couldn't keep up with the growing demand for paper. The United States alone was using 250 thousand tons of rags each year. And a quarter of that had to be imported. It was clear that a new source of fiber was needed to keep up with the demand for paper. The answer to this problem turned out to be paper made from wood pulp, something that was abundantly available in north America. IN Canada, the first wood pulp mill was set up in 1866 and it was immediately successful. But while wood pulp solved the problem of quantity it created a problem of quality. Wood contains a substance called lignin. The simplest way to make large quantities of cheap paper involved leaving the lignin in the wood pulp. But lignin is acidic and its presence in paper has shorten the life expectancy of paper from several centuries for rag pager to less than a century for paper made from wood pulp. This means that books printed less than a hundred years ago are already turning yellow and beginning to disintegrate, even though books printed much earlier maybe in the conditions. This is bad enough for the older books on your bookshelf but it opposes a huge problem for libraries and the collections of government documents.

38. What does the speaker mainly discuss? 

39. What did the paper industry need a new source of fiber in the early 1800s?

40. What can inferred about the first wood pulp mill in Canada?

41. According to the speaker, what is the problem with lignin?

42. According to the speaker, what problem do libraries face?

43 to 47 Radio announcer talking about a current topic.
A recent report has shown that here in the United States, we've experienced an evolution concerning our attitudes towards the workweek and the weekends. Although some calendars still mark the beginning of a week as Sunday, more and more of us are coming to regard Monday as the first day of the week with Saturday and Sunday comprising the two-day period thought as the weekend. In fact the word "weekend" didn't even exist in English until about the middle of last century. In England at that time, Saturday afternoons had just been added to Sundays and holidays as a time for workers to have off from their jobs. This innovation became common in the United States in the 1920s, but as the workweek were shortened during the Great Depression of the 1930s, the weekend expanded to two full days - Saturday and Sunday. Some people thought that this trend would continue due to increasing automation and the workweek might decrease to four days or even fewer. But so far this hasn't happened. The workweek seems to have stabilized as forty hours made up of five eight-hour days. After this commercial I'll be back to talk about the idea of adding Monday to the weekend.

43. What is the speaker mainly discussing?

44. According to the speaker, what is changing in the way people think about the week?

45. According to the speaker, how has the amount of time people work changed from the early part of the century?

46. What does the speaker imply about the workweek in England in early 1800s?

47. According to the speaker, what affect did some people think the increasing use of automation would have?

48 to 50 A professor talking to her music students.
I don't think I have told you about my trip to Tanglewood's music festival. When I was in college, I won a music competition and the prize was a week at Tanglewood. Anyway it is one of the world's most famous music festivals and the summer pome the Boston Symphony Orchestra. It is located in the beautiful Berkshire Hills in New England. The summer musical season consists given over about mine weeks: from just 1st through the first week in September. The biggest  stars on the music scene appear here. The year I went I was Lucky enough to see Leonard Bemstein conducting. I understand it is sometimes hard to get tickets but of course mine were a part of the prize. If you want to sit inside the tickets are expensive. It's much cheaper to sit outside on the lawn. But it might rain, or sometimes it is really cool even in the summer. Either way the sound system is excellent. So it doesn't really matter where you sit. I seem to recall that the festival got started in the 1930s. Some Berkshire residents invited a symphony orchestra to perform a few outdoor concerts. The concerts were so successful that after a couple of years that things really took off. And the festival has got bigger and better every year. Attending was such a wonderful experience. I'd love to be able to go again. And I hope that all of you would be able to go too.

48. Why did the professor originally go to Tanglewood?

49. According to the professor, what is the disadvantage of sitting on the lawn?

50. What does the professor imply about the festival?

51. What is the killdeer's nest in parking lot an example of?  (A)

52. According to the speaker, what is a possible reason that birds began to build nests in trees?  (A)

1996年10月托福閱讀全真試題

Question 1-8

When Jules Verne wrote Journey to the Center of the
Earth in 1864, there were many conflicting theories about the
nature of the Earth's interior. Some geologists thought that it
contained a highly compressed ball of incandescent gas, while
others suspected that it consisted of separate shells, each made
of a different material. Today, well over a century later, there
is still little direct evidence of what lies beneath our feet. Most
of our knowledge of the Earth's interior comes not from mines
or boreholes, but from the study of seismic waves - powerful
pulses of energy released by earthquakes.

The way that seismic waves travel shows that the Earth's
interior is far from uniform. The continents and the seabed
are formed by the crust - a thin sphere of relatively light, solid
rock. Beneath the crust lies the mantle, a very different layer
that extends approximately halfway to the Earth's center.
There the rock is the subject of a battle between increasing
heat and growing pressure.

In its high levels, the mantle is relatively cool; At greater
depths, high temperatures make the rock behave more like a
liquid than a solid. Deeper still, the pressure is even more
intense, preventing the rock from melting in spite of a
higher temperature.

Beyond a depth of around 2,900 kilometers, a great
change takes place and the mantle gives way to the core. Some
seismic waves cannot pass through the core and others are bent
by it. From this and other evidence, geologists conclude that
the outer core is probably liquid, with a solid center. It is
almost certainly made of iron, mixed with smaller amounts
of other elements such as nickel.

The conditions in the Earth's core make it a far more
alien world than space. Its solid iron heart is subjected to
unimaginable pressure and has a temperature of about 9,000oF.
Although scientists can speculate about its nature, neither
humans nor machines will ever be able to visit it.

1. The word "conflicting" in line 2 is closest in meaning to

(A) controlling
(B) outdated
(C) opposing
(D) important

2. What is today's richest source of information about the Earth's interior for geologists?

(A) Boreholes
(B) Shells
(C) Seismic waves
(D) Mines

3. The word "There" in line 16 refers to the

(A) mantle
(B) crust
(C) seabed
(D) Earth's center.

4. Which of the following is a primary characteristic of the Earth's mantle?

(A) Light, solid rock
(B) Uniformity of composition
(C) Dramatically increasing pressure
(D) Compressed, incandescent gas

5. The phrase "gives way to" in line 24 is closest in meaning to

(A) runs along
(B) rubs against
(C) turns into
(D) floats on

6. The word "it" in line 26 refers to

(A) mantle
(B) core
(C) change
(D) depth

7. Why does the author state in line 30-31 that the Earth's core is "more alien" than space?

(A) Government funds are not available to study the Earth's core.
(B) Scientists aren't interested in the characteristics of the Earth's core.
(C) It is impossible to go to the Earth's core to do research.
(D) The Earth's core is made of elements that are dangerous to humans.

8. The word "speculate" in line 33 is closest in meaning to

(A) report
(B) learn
(C) worry
(D) hypothesize


Question 9-20

Despite the road improvements of the turnpike era (1790-
1830). Americans continued as in colonial times to depend
wherever possible on water routes for travel and transportation.
The larger rivers, especially the Mississippi and the
Ohio, became increasingly useful as steamboats grew in
number and improved in design.

River boats carried to New Orleans the corn and other
crops of northwestern farmers, the cotton and tobacco of
southwestern planters. From New Orleans, ships took the
cargoes on to eastern seaports. Neither the farmers of the west
nor the merchants of the east were completely satisfied with
this pattern of trade. Farmers could get better prices for their
crops if the alternative existed of sending them directly eastward
to market and merchants could sell larger quantities of
their manufactured goods if these could be transported more
directly and more economically to the west.

New waterways were needed. Sectional jealousies and
constitutional scruples stood in the way of action by the federal
government and necessary expenditures were too great for
private enterprise. If extensive canals were to be dug, the job
would be up to the various states.

New York was the first to act. It had the natural advantage
of a comparatively level route between the Hudson River
and Lake Erie, through the only break in the entire
Appalachian Mountain chain. Yet the engineering tasks were
imposing. The distance was more than 350 miles and there
were ridges to cross and a wilderness of woods and swamps to
penetrate. The Erie Canal begun in 1817 and completed in
1825, was by far the greatest construction job that Americans
had ever undertaken. It quickly proved a financial success as
well. The prosperity of the Erie encouraged the state to
enlarge its canal system by building several branches.
The range of the New York canal system was still further
extended when the states of Ohio and Indiana, inspired by the
success of the Erie Canal, provided water connections between
Lake Erie and the Ohio River.

9. What does the passage suggest was the principal route for transporting crops to the east prior in 1825?

(A) River to road
(B) Canal to river
(C) River to ocean
(D) Road to canal.

10.It can be inferred from the passage that shipping cargo east by way of New Orleans was

(A) Advantageous for manu factures
(B) Inexpensive for merchants
(C) Not economical for farmers
(D) Considered economical by the government

11.The word "alternative" in line 13 is closest in meaning to

(A) option
(B) transition
(C) intention
(D) authorization

12.The word "them" in line 9 refers to

(A) crops
(B) farmers
(C) prices
(D) merchants

13.Which of the following products would a northwestern farmer in the early nineteenth century be most likely to purchase from the east?

(A) Grain
(B) Vegetables
(C) Textiles
(D) Fruit.

14.According to the passage, where was the Erie Canal located?

(A) Between Ohio and Indiana.
(B) Along the Appalachian Mountains
(C) Between Lake Erie and the Ohio River
(D) Across New York State.

15.The word "imposing" in line 26 could best be replaced by

(A) impractical
(B) successful
(C) demanding
(D) misleading

16.The word "penetrate" in line 28 is closest in meaning to

(A) cut down
(B) go through
(C) fill up
(D) take over

17.The word "its" in line 32 refers to

(A) prosperity
(B) Erie
(C) System
(D) State

18.The word "extended" in line 34 is closest in meaning to

(A) increased
(B) constructed
(C) deepened
(D) measured

19.According to the passage, Indiana and Ohio supported the development of the New York canal system by

(A) helping to build the Erie Canal.
(B) Building branches to connect it with the Ohio River
(C) Providing much of the water for the Erie Canal.
(D) Contributing financially to the construction costs

20.What does the paragraph following the passage probably discuss?

(A) Industry on Lake Erie
(B) Canals in Ohio and Indiana
(C) Sectional jealousies in Indiana and Ohio
(D) Travel on the Erie Canal.


Question 21-31

Legend has it that sometime toward the end of the Civil
War (1861-1865) a government train carrying oxen traveling
through the northern plains of eastern Wyoming was caught in
a snowstorm and had to be abandoned. The driver returned
the next spring to see what had become of his cargo. Instead
of the skeletons he had expected to find, he saw his oxen,
living, fat, and healthy. How had they survived?

The answer lay in a resource that unknowing Americans
lands trampled underfoot in their haste to cross the "Great
American Desert" to reach lands that sometimes proved
barren. In the eastern parts of the United States, the preferred
grass for forage was a cultivated plant. It grew well with
enough rain, then when cut and stored it would cure and
become nourishing hay for winter feed. But in the dry grazing
lands of the West that familiar bluejoint grass was often killed
by drought. To raise cattle out there seemed risky or even
hopeless.

Who could imagine a fairy-tale grass that required no rain
and somehow made it possible for cattle to feed themselves all
winter? But the surprising western wild grasses did just that.
They had wonderfully convenient features that made them
superior to the cultivated eastern grasses. Variously known as
buffalo grass, grama grass, or mesquite grass, not only were
they immune to drought; but they were actually preserved by
the lack of summer and autumn rains. They were not juicy
like the cultivated eastern grasses, but had short, hard stems.
And they did not need to be cured in a barn, but dried right
where they grew on the ground. When they dried in this way,
they remained naturally sweet and nourishing through the
winter. Cattle left outdoors to fend for themselves thrived on
this hay. And the cattle themselves helped plant the fresh
grass year after year for they trampled the natural seeds
firmly into the soil to be watered by the melting snows of winter
and the occasional rains of spring. The dry summer air cured
them much as storing in a barn cured the cultivated grasses.

21.What does the passage mainly discuss?

(A) Western migration after the Civil War
(B) The climate of the western United States
(C) The raising of cattle.
(D) A type of wild vegetation

22.What can be inferred by the phrase "Legend has it" in line 1?

(A) The story of the train may not be completely factual.
(B) Most history books include the story of the train.
(C) The driver of the train invented the story.
(D) The story of the train is similar to other ones from that time period.

23.The word "they" in line 7 refers to

(A) plains
(B) skeletons
(C) oxen
(D) Americans

24.What can be inferred about the "Great American Desert" mentioned in line 9-10?

(A) It was not originally assumed to be a fertile area.
(B) Many had settled there by the 1860's.
(C) It was a popular place to raise cattle before the Civil War.
(D) It was not discovered until the late 1800's.

25.The word "barren" in line 10 is closest in meaning to

(A) lonely
(B) dangerous
(C) uncomfortable
(D) infertile.

26.The word "preferred" in line 11 is closest in meaning to

(A) ordinary
(B) available
(C) required
(D) favored

27.Which of the following can be inferred about the cultivated grass mentioned in the second paragraph?

(A) Cattle raised in the western United States refused to eat it.
(B) It would probably not grow in the western United States.
(C) It had to be imported into the United States.
(D) It was difficult for cattle to digest.

28.Which of the following was NOT one of the names given to the Western grasses?

(A) Grama grass
(B) Bluejoint grass
(C) Buffalo grass
(D) Mesquite grass

29.Which of the following was NOT mentioned as a characteristic of western grasses?

(A) They have tough stems.
(B) They are not affected by dry weather.
(C) They can be grown indoors.
(D) They contain little moisture.

30.The word "hard" in line 26 is closest in meaning to

(A) firm
(B) severe
(C) difficult
(D) bitter

31.According to the passage, the cattle helped promote the growth of the wild grasses by

(A) stepping on and pressing the seeds into the ground
(B) naturally fertilizing the soil
(C) continually moving from one grazing area to another
(D) eating only small quantities of grass.


Question 32-44

Seventeenth-century houses in colonial North America
were simple structures that were primarily functional carrying
over traditional designs that went back to the Middle Ages.
During the first half of the eighteenth century, however,
houses began to show a new elegance. As wealth increased,
more and more colonists built fine houses.

Since architecture was not yet a specialized profession in
the colonies, the design of buildings was left either to amateur
designers or to carpenters who undertook to interpret architectural
manuals imported from England. Inventories of colonial
libraries show an astonishing number of these handbooks for
builders, and the houses erected during the eighteenth century
show their influence. Nevertheless, most domestic architecture
of the first three-quarters of the eighteenth century
displays a wide divergence of taste and freedom of application of
the rules laid down in these books.

Increasing wealth and growing sophistication throughout
the colonies resulted in houses of improved design, whether
the material was wood, stone, or brick. New England still
favored wood, though brick houses became common in Boston
and other towns, where the danger of fire gave an impetus to
the use of more durable material. A few houses in New
England were built of stone, but only in Pennsylvania and adjacent
areas was stone widely used in dwellings. An increased use of
brick in houses and outbuildings is noticeable in Virginia and
Maryland, but wood remained that most popular material evenin houses built by wealthy landowners. In the Carolinas, even
in closely packed Charleston, wooden houses were much more
common than brick houses.

Eighteenth-century houses showed great interior improvements
over their predecessors. Windows were made larger
and shutters removed. Large, clear panes replaced the small
leaded glass of the seventeenth century. Doorways were larger
and more decorative. Fireplaces became decorative features of
rooms. Walls were made of plaster or wood, sometimes elaborately
paneled. White paint began to take the place of blues,
yellows, greens, and lead colors, which had been popular for
walls in the earlier years. After about 1730, advertisements
for wallpaper styles in scenic patterns began to appear in
colonial newspapers.

32.What does the passage mainly discuss?

(A) The improved design of eighteenth-century colonial houses.
(B) A comparison of eighteenth-century houses and modern houses.
(C) The decorations used in eighteenth-century houses.
(D) The role of carpenters in building eighteenth-century houses.

33. What was one of the main reasons for the change in architectural style in eighteenth-century North America?

(A) More architects arrived in the colonies.
(B) The colonists developed an interest in classical architecture.
(C) Bricks were more readily available.
(D) The colonists had more money to spend on housing.

34.According to the passage, who was responsible for designing houses in eighteenth-century NorthAmerica?

(A) Professional architects
(B) Customers
(C) Interior decorators
(D) Carpenters.

35.The passage implies that the rules outlined in architectural manuals were

(A) generally ignored
(B) legally binding
(C) not strictly adhered to
(D) only followed by older builders

36.The word "divergence" in line 15 is closest in meaning to

(A) description
(B) development
(C) difference
(D) display

37.The word "durable" in line 22 is closest in meaning to

(A) attractive
(B) expensive
(C) refined
(D) long-lasting

38.Where was stone commonly used to build houses?

(A) Virginia
(B) Pennsylvania
(C) Boston
(D) Charleston

39.The word "dwellings" in line 24 is closest in meaning to

(A) houses
(B) towns
(C) outbuildings
(D) rural areas

40.The word "predecessors" in line 31 refers to

(A) colonist who arrived in North America in the seventeenth century.
(B) houses constructed before the eighteenth century
(C) interior improvements
(D) wooden houses in Charleston

41.The author mentions elaborately paneled walls in line 35-36 as an example of

(A) how the interior design of colonial houses was improved.
(B) why walls were made of wood or plaster.
(C) How walls were made stronger in the eighteenth century.
(D) What kind of wood was used for walls after 1730.

42.The word "elaborately" in line 35-36 is closest in meaning to

(A) done in great detail
(B) put together carefully
(C) using many colors
(D) reinforced structurally

43.What does the author imply about the use of wallpaper before 1730?

(A) Wallpaper samples appeared in the architectural manuals.
(B) Wallpaper was the same color as the wall paints used
(C) Patterned wallpaper was not widely used.
(D) Wallpaper was not used in stone house.

44.Where in the passage does the author give a reason why brick was the preferred material for houses in some urban areas?

(A) Lines 9-11
(B) Lines 13-15
(C) Lines 17-19
(D) Lines 23-24


Question 45-50

Bloodhounds are biologically adapted to trailing their
prey. The process by which the nose recognizes an odor is not
fully understood, but there are apparently specific receptor
sites for specific odors. In one explanation, recognition occurs
when a scent molecule fits into its corresponding receptor site,
like a key into a lock, causing a mechanical or chemical change
in the cell. Bloodhounds apparently have denser concentrations
of receptor sites tuned to human scents.

When a bloodhound trails a human being, what does it
actually smell? The human body, which consists of about 60
trillion living cells, sheds exposed skin at a rate of 50 million
cells a day. So even a trail that has been dispersed by breezes
may still seem rich to a bloodhound. The body also produces
about 31 to 50 ounces of sweat a day. Neither this fluid nor
the shed skin cells have much odor by themselves, but the
bacteria working on both substances is another matter. One
microbiologist estimates the resident bacteria population of a
clean square centimeter of skin on the human shoulder at
"multiples of a million." As they go about their daily business
breaking down lipids, or fatty substances, on the skin, these
bacteria release volatile substances that usually strike the
bloodhound's nose as an entire constellation of distinctive
scents.

45.What does the passage mainly discuss?

(A) Why people choose bloodhounds for household pets
(B) How a bloodhound's sense of smell works
(C) How humans compensate for an underdeveloped sense of smell
(D) The way in which bacteria work on skin cells and body sweat.

46.The author compares a scent molecule with a

(A) key
(B) lock
(C) cell
(D) bloodhound

47.In line 9, the word "it" refers to

(A) bloodhound
(B) human being
(C) smell
(D) body

48.According to the passage, how many cells of skin does the human body rid itself of every day?

(A) 60 trillion
(B) 50 million
(C) 1 million
(D) Between 31 and 50

49.In line 13, the word "rich" is used to mean that a trail is

(A) paved with precious materials
(B) a profitable business to get into
(C) a very costly undertaking
(D) filled with an abundance of clues.

50.Which of the following acts as a stimulus in the production of the human scent?

(A) Sweat
(B) Dead skin cells
(C) Bacteria
(D) Fatty substances.