[求助]00年5月和8月的几道阅读题

0005The canopy ,the upper level of the trees in the rain forest, holds a plethora of climbing mammals of moderately large size, which may include monkeys, cats, civets, and porcupines. Smaller species, including such rodents as mice and small squirrels ,are not

      as prevalent overall in high tropical canopies as they are in most habitats globally.

(5)   Small mammals, being warm blooded, suffer hardship in the exposed and turbulent

environment of the uppermost trees. Because a small body has more surface area per unit

of weight than a large one of similar shape, it gains or loses heat more swiftly. Thus, in

the trees, where shelter from heat and cold may be scarce and conditions may fluctuate, a

small mammal may have trouble maintaining its body temperature.

(10)      Small size makes it easy to scramble among twigs and branches in the canopy for

insects, flowers, or fruit, but small mammals are surpassed, in the competition for food,

by large ones that have their own tactics for browsing among food-rich twigs. The weight

of a gibbon (a small ape) hanging below a branch arches the terminal leaves down so that

fruit-bearing foliage drops toward the gibbon’s face. Walking or leaping species of a  

(15)   similar or even larger size access the outer twigs either by snapping off and retrieving the

whole branch or by clutching stiff branches with the feet or tail and plucking food with

their hands.

    Small climbing animals may reach twigs readily, but it is harder for them than for large

climbing animals to cross the wide gaps from on tree crown to the next that typify the

(20)   high canopy. A macaque or gibbon can hurl itself farther than a mouse can: it can achieve

a running start, and it can more effectively use a branch as a springboard, even bouncing

on a climb several times before jumping. The forward movement of a small animal is

seriously reduced by the air friction against the relatively large surface area of its body.

Finally, for the many small mammals that supplement their insect diet with fruits or seeds

(25)   an inability to span open gaps between tree crowns may be problematic, since trees that

yield these foods can be sparse.

4. According to paragraph 2, which of the

  following is true about the small mammals in

  the rain forest?

(A) They have body shapes that are adapted to

   life in the canopy.

(B) They prefer the temperature and climate of

   the canopy to that of other environments.

(C) They have difficulty with the changing

   conditions in the canopy.

(D) They use the trees of the canopy for shelter

   from heat and cold.

Question 30

During most of their lives, surge glaciers behave like normal glaciers, traveling perhaps

only a couple of inches per day. However, at intervals of 10 to 100 years, these glaciers

move forward up to 100 times faster than usual. The surge often progresses along a glacier

line     like a great wave, proceeding from one section to another. Subglacial streams of meltwater

(5)      water pressure under the glacier might lift it off its bed, overcoming the friction between ice

and rock, thus freeing the glacier, which rapidly sliders downhill Surge glaciers also might

be influenced by the climate, volcanic heat, or earthquakes. However, many of these

glaciers exist in the same area as normal glaciers, often almost side by side.

(10)     Some 800 years ago, Alaska’s Hubbard Glacier advanced toward the sea, retreated, and

advanced again 500 years later. Since 1895, this secentry-mile-long river of ice has been

flowing steadily toward the Gulf of Alaska at a rate of approximately 200 feet per year. In

June 1986, however, the glacier surged ahead as much as 47 feet a day. Meanwhile, a

western tributary, called Valerie Glacier, advanced up to 112 feet a day. Hubbard’s surge

(15)     closed off Russell Fiord with a formidable ice dam, some 2,500 feet wide and up to 800

           feet high, whose caged waters threatened the town of Yakutat to the south.

   About 20 similar glaciers around the Gulf of Alaska are heading toward the sea. If

enough surge glaciers reach the ocean and raise sea levels, West Antarctic ice shelves could

rise off the seafloor and become adrift. A flood of ice would then surge into the Southern

(20)   Sea. With the continued rise in sea level, more ice would plunge into the ocean, causing sea

levels to rise even highter, which in turn would release more ice and set in motion a vicious

cycle. The additional sea ice floating toward the tropics would increase Earth’s albedo and

lower global temperatures, perhaps enough to initiate a new ice age. This situation appears

to have occurred at the end of the last warm interglacial (the time between glacations),

(25)     called the Sangamon, when sea ice cooled the ocean dramatically, spawning the beginning

of the Ice Age.

The asphalt at La Brea seeps to the surface, especially in the summer, and forms

shallow puddles that would often have been concealed by leaves and dust. Unwary

animals would become trapped on these thin sheets of liquid asphalt, which are extremely

sticky in warm weather. Stuck, the unfortunate beasts would die of exhaustion and

(20)   hunger or fall prey to predators that often also became stuck.

                               As the animals decayed, more scavengers would be attracted and caught in their turn.

Carnivores greatly outnumber herbivores in the collection: for every large herbivore,

      there is one saber-tooth cat, a coyote, and four wolves. The fact that some bones are

      heavily weathered shows that some bodies remained above the surface for weeks or

  (25) months. Bacteria in the asphalt would have consumed some of the tissues other than

              bones, and the asphalt itself would dissolve what was left, at the same time impregnating

      and beautifully preserving the saturated bones, rendering then dark brown and shiny.

1.What aspect of the La Brea tar pits does the

  passage mainly discuss?

(A)The amount of asphalt that was mined there

(B) The chemical and biological interactions

   between asphalt and animals

(C) The fossil remains that have been found

   there

(D) Scientific methods of determining the age

   of tar pits