passage 17

Archaeology is a source of history, not just a humble auxiliary discipline. Archaeological data are historical documents in their own right, not mere illustrations to written texts. Just as much as any other historian, an archaeologist studies and tries to reconstitute the process that has created the human world in which we live – and us ourselves in so far as we are each creatures of our age and social environment. Archaeological data are all changes in the material world resulting from human action or more succinctly, the fossilized results of human behavior. The sum total of these constitute what may be called the archaeological record. This record exhibits certain peculiarities and deficiencies the consequences of which produce a rather superficial contrast between archaeological history and the more familiar kind based upon written records.

Not all human behavior fossilizes. The words I utter and you hear as vibrations in the air are certainly human changes in the material world and may be of great historical significance. Yet they leave no sort of trace in the archaeological records unless they are captured by a dictaphone or written down by a clerk. The movement of troops on the battlefield may “change the course of history”, but this is equally ephemeral from the archaeologist’s standpoint. What is perhaps worse, most organic materials are perishable. Everything made of wood, hide wool, linen, grass, hair, and similar materials will decay and vanish in dust in a few years or centuries, save under very exceptional conditions. In a relatively brief period the archaeological record is reduced to mere scraps of stone, bone, glass, metal, and earthenware. Still modern archaeology, by applying appropriate techniques and comparative methods aided by a few lucky finds from peat bogs, deserts, and frozen soils, is able to fill up a good deal of the gap.

1.What is the author’s main purpose in the passage?

2. According to the passage, the archaeological record consists of …………… .

3.The word “they” in paragraph 2 refers to …………… .

4.Which of the following is NOT mentioned as an example of an organic material?

5.The author mentions all of the following archaeological discovery sites EXCEPT …………… .

6. The paragraph following the passage most probably discusses …………… .

Passage 18

What makes it rain? Rain falls from clouds for the same reason anything falls to Earth. The Earth’s gravity pulls it. But every cloud is made of water droplets or ice crystals. Why doesn’t rain or snow fall constantly from all clouds? The droplets or ice crystals in clouds are exceedingly small. The effect of gravity on them is minute. Air currents move and lift droplets so that the net downward displacement is zero, even though the droplets are in constant motion.

Droplets and ice crystals behave somewhat like dust in the air made visible in a shaft of sunlight. To the casual observer, dust seems to act in a totally random fashion, moving about chaotically without fixed direction. But in fact dust particles are much larger than water droplets and they finally fall. The cloud droplet of average size is only 1/2500 inch in diameter. It is so small that it would take sixteen hours to fall half a mile in perfectly still air, and it does not fall out of moving air at alt. Only when the droplet grows to a diameter of 1/125 inch or larger can it fall from the cloud. The average raindrop contains a million times as much water as a tiny cloud droplet. The growth of a cloud droplet to a size large enough to fall out is the cause of rain and other forms of precipitation. This important growth process is called “coalescence.”

1.What is the main topic of the passage?

3.Why don’t all ice crystals in clouds immediately fall to earth?

4.The word “motion” in paragraph 1 is closest in meaning to which of the following?

5.What can be inferred about drops of water larger than 1/125 inch in diameter?

6. In the last line, what does the term “coalescence” refer to?

7. What is the diameter of the average cloud droplet?

Passage 19

The beaver is North America’s largest rodent. As such, it is a close relative of two creatures that are not held in particularly high regard by most connoisseurs of wildlife, the porcupine and the rat. Even so, the beaver has several qualities that endear it to people: it is monogamous and lives in a family unit; it is gentle and clean; it is absolutely industrious.

The beaver’s legendary capacity for hard work has produced some astonishing results. In British Columbia, for example, one ambitious creature felled a cottonwood tree that was 11.1 feet tall and more than five feet thick. In New Hampshire, beavers constructed a dam that was three-fourths of a mile long and the body of water it created contained no fewer than 40 lodges. In Colorado, beavers were responsible for the appearance of a canal that was a yard deep and ran for 7511 feet. Each adult beaver in Massachusetts, according to one researcher’s calculations, cuts down more than a ton of wood every year.

Beavers appear to lead exemplary lives. But the beaver’s penchant for building dams, lodges, and canals has got it into a lot of hot water lately. People who fish in the Midwest and New England are complaining about beaver dams that spoil streams for trout and in the Southeast, loggers object whenever the animals flood out valuable stands of commercial timber. But some beaver experts champion a more charitable view. Historically, they say, this creature’s impact on the environment has been tremendously significant, and its potential as a practical conservation resource is receiving more and more attention.

1. What does the passage mainly discuss?

2. In the first paragraph, the author implies that the porcupine and the rat are …………… .

3. According to the passage, a beaver in British Columbia was responsible for …………… .

4. In paragraph 2, what does the word “it” refer to?

5. According to the passage, beavers have been the subject of complaints because they …………… .

6. The paragraph following the passage most probably discusses …………… .

Passage 20

Early experiments in light-sensitive images were conducted in France by the chemist Joseph N. Niepce. When he died in 1833, Niepce’s photography process was taken up and perfected by Louis J. M. Daguerre.

Daguerre’s procedure involved coating a copper plate with a light-sensitive emulsion, which, when exposed to light for 5 to 40 minutes, produced an image on the plate. Because there was no negative, as in modern film, the image, called a daguerreotype, was unique and could not be duplicated. In August 1839, he made his process public, and word of it spread far and wide.

After accounts of Daguerre’s process appeared in United States newspapers, a Philadelphian, Joseph Saxon, produced what is believed to be the first daguerreotype in the United States. Robert Cornelius, a manufacturer of metal lamps in Philadelphia, was also one of the first to produce daguerreotypes, operating a studio from 1839 to 1842. His partner, Dr. Paul Beck Goddard, a chemistry professor at the University of Pennsylvania, discovered bromine, which reduced the exposure time necessary to produce an image sufficiently to make posing for a portrait possible. Philadelphia’s credentials as an early center of photography were further established by the exhibitions of daguerreotypes held at the Franklin Institute and the American Philosophical Society in late 1839 and 1840.

In New York, the painter Samuel F. B. Morse was influential in the dissemination of the daguerreotype process. Morse had been in Paris in 1839 and knew Daguerre. When he returned, he began advocating the use of the daguerreotype process by artists – as president of the National Academy of Design, he was in a good position to do so.

The original camera was little more than a wooden box with a lens at one end and a sensitized plate at the other. The process of making a daguerreotype required only some mechanical aptitude and a little knowledge of chemistry, but no artistic talent. Suddenly anyone could produce images. This in itself effected a revolution in picture making. By 1853 there were reportedly 2,000 aguerreotypists practicing in the United States, most of whom were in the business to make money, not art. However, although the majority of early daguerreotypes had a relatively low aesthetic threshold, there were many powerful images among them showing perceptive observation and great exactitude in every detail.

1. What does the passage mainly discuss?

2. Which of the following differences between a modern camera and the daguerreotype process is mentioned in the passage?

3. The word “it” in paragraph 2 refers to …………… .

4. How did Joseph Saxon learn how to make daguerreotypes?

5. It can be inferred that daguerreotype portraits were rarely made before the discovery of bromine because …………… .

6.The word “dissemination” in paragraph 4 is closest in meaning to …………… .

7. The word “advocating” in paragraph 4 is closest in meaning to …………… .

8. Why does the author mention the National Academy of Design in paragraph 4?

9. The phrase “little more than” in paragraph 5 is closest in meaning to …………… .

10. The author mentions “2,000 daguerreotypists” in paragraph 5 to support the idea that ……………

11. What does the author imply by stating in the passage that most early daguerreotypes had a relatively low aesthetic threshold in the last paragraph?