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Typical of the grassland dwellers of the continent is the American antelope or pronghorn.

Of the millions who saw Haley’s comet in 1986, how many people will live long enough to see it return in the twenty-first century?

Anthropologists have discovered that fear, happiness, sadness, and surprise are universally reflected in facial expressions.

Because of its irritating effect on humans, the use of phenol as a general anti-septic has been largely discontinued.

In group to remain in existence, a profit-making organization must, in the long run, produce something consumers consider useful or desirable.

The greater the population there is in a locality, the greater the need there is for water, transportation, and disposal of refuse.

It is more difficult to write simply, directly, and effectively than to employ flowery but vague expressions that only obscure one’s meaning.

With modern offices becoming more mechanized, designers are attempting to personalize them with warmer, less severe interiors.

The difference between libel and slander is that libel is printed while slander is spoken.

The knee is the joints where the thigh bone meets the large bone of the lower leg.

Acids are chemical compounds that, in water solution, have a sharp taste, a corrosive action on metals, and the ability to turn certain blue vegetable dyes red.

Billie Holiday’s reputation as a great jazz-blues singer, rests on her ability to give emotional depth to her songs.

Essentially, a theory is an abstract, symbolic representation of what is conceived to be a reality.

Long before children are able to speak or understand a language, they communicate through facial expressions and by making noises.

Thanks to modern irrigation, crops now grow abundantly in areas where once nothing but cacti and sagebrush could live.
The development of mechanical timepieces spurred the search for more accurate sundials, with which to regulate them.

Anthropology is a science in that anthropologists use a rigorous set of methods and techniques to do observations that can be checked by others.

Fungi are important in the process of decay, which returns ingredients to the soil, enhances soil fertility, and decomposes animal debris.

When it is struck, a tuning fork produces an almost pure tone, retaining its pitch over a long period of time.

Although pecans are most plentiful in the South-Eastern part of the United States, they are found as far north as Ohio and Illinois.

Eliminating problems by transferring the blame to others is often called scapegoating.

The chief foods eaten in any country depend largely on what grows best in its climate and soil.

Over a very large number of trials, the probability of an event’s occurring is equal to the probability that it will not occur.

Most substance contract when they freeze, so that the density of a substance’s solid is higher than the density of its liquid.

The mechanism by which brain cells store memories is not clearly understood.

By the middle of the twentieth century, painters and sculptors in the United States had begun to exert a great world-wide influence over art.

In the eastern part of New Jersey lies the city of Elizabeth, a major shipping and manufacturing center.

Elizabeth Blackwell, the first woman medical doctor in the United States, founded the New York Infirmary, an institution that has always had a completely female medical staff.

Alexander Graham Bell once told his family that he would rather be remembered as a teacher of the deaf than as the inventor of the telephone.

Because its leaves remain green long after being picked, rosemary became associated with the idea of remembrance.
Although apparently rigid, bones exhibit a degree of elasticity that enables the skeleton to withstand considerable impact.

That xenon could not FORM chemical compounds, was once believed by scientists.

Research into the dynamics of storms is directed toward improving the ability to predict these events and thus to minimize damage and avoid loss of life.

The elimination of inflation would ensure that the amount of money used in repaying a loan would have the same value as the amount of money borrowed.

Futurism, an early twentieth-century movement in art, rejected all traditions and attempted to glorify contemporary life by emphasizing the machine and motion.

One of the wildest and most inaccessible parts of the United States is the Everglades where wildlife is abundant and largely protected.

Lucretia Mott’s influence was so significant that she has been credited by some authorities as the originator of feminism in the United States.

The activities of the international marketing researcher, are frequently much broader than those of the domestic marketer.

The continental divide refers to an imaginary line in the North American Rockies that divides the waters flowing into the Atlantic Ocean from those flowing into the Pacific.

Studies of the gravity field of the Earth indicate that its crust and mantle yield when unusual weight is placed on them.

The annual worth of Utah’s manufacturing is greater than that of its mining and farming combined.

The wallflower is so called because its weak stems often grow on walls and along stony cliffs for support.

It is the interaction between people, rather than the events that occur in their lives, that is the main focus of social psychology.

No social crusade aroused Elizabeth Williams’ enthusiasm more than the expansion of educational facilities for immigrants to the United States.
Quails typically have short rounded wings that enable them to spring into full flight instantly when disturbed in their hiding places.

According to anthropologists, the earliest ancestors of humans that stood upright resembled chimpanzees facially, with sloping foreheads and protruding brows.

Not until 1866 was the fully successful transatlantic cable finally laid.

In his writing, John Crowe Ransom describes what he considers the spiritual barrenness of society brought about by science and technology.

Children with parents whose guidance is firm, consistent, and rational are inclined to possess high levels of self-confidence.

The ancient Hopewell people of North America probably cultivated corn and other crops, but hunting and gathering were still of critical importance in their economy.

Using many symbols makes it possible to put a large amount of information on a single map.

Anarchism is a term describing a cluster of doctrines and attitudes whose principal uniting feature is the belief that government is both harmful and unnecessary.
Probably no man had more effect on the daily lives of most people in the United States than did Henry Ford a pioneer in automobile production.

The use of well-chosen nonsense words makes possible the testing of many basic hypotheses in the field of language learning.

The history of painting is a fascinating chain of events that probably began with the very first pictures ever made.

Perfectly matched pearls, strung into a necklace, bring a far higher price than the same pearls sold individually.

During the eighteenth century, Little Turtle was chief of the Miami tribe whose territory became what is now Indiana and Ohio.

Among almost seven hundred species of bamboo, some are fully grown at less than a-foot-high, while others can grow three feet in twenty-four hours.

Before starting on a sea voyage, prudent navigators learn the sea charts, study the sailing directions, and memorize lighthouse locations to prepare themselves for any conditions they might encounter.

Of all the economically important plants, palms have been the least studied.

Buyers and sellers should be aware of new developments in technology can and does affect marketing activities.

The application of electronic controls made possible by the microprocessor and computer storage have multiplied the uses of the modern typewriter.

The human skeleton consists of more than two hundred bones bound together by tough and relatively inelastic connective tissues called ligaments.

The pigmentation of a pearl is influenced by the type of oyster in which it develops and by the depth, temperature, and the salt content of the water in which the oyster lives.

Although mockingbirds superbly mimic the songs and calls of many birds, they can none-the-less be quickly identified as mockingbirds by certain aural clues.

Not only can walking fish live out of the water, but they can also travel short distances over land.

Scientists do not know why dinosaurs became extinct, but some theories postulate that changes in geography, climate, and sea levels were responsible.

The science of horticulture(园林艺术), in which the primary concerns are maximum yield and superior quality, utilizes information derived from other sciences.

Snow aids farmers,by keeping the heart in the lower ground levels, thereby saving the seeds from freezing.

Even though the precise qualities of the hero in literary words may vary over time, the basic exemplary (模范) function of the hero seems to remain constant.

People in prehistoric times created paints by grinding materials such as plants and clay into powder and then adding water.

Often very annoying weeds, golden-rods crowd out less hardy plants and act as hosts to many insect pests.

Starting around 7000 B.C., and for the next four thousand years, much of the Northern Hemi-sphere experienced temperatures warmer than at present.
When Henry Ford first sought financial backing for making cars, the very notion of farmers and clerks owning automobiles was considered ridiculous.

Though once quite large, the population of the bald eagle across North America has drastically declined in the past forty years.

The beaver chews down trees to get food and material with which to build its home.

Poodles were once used as retrievers in duck hunting, but the American Kennel Club does not consider them sporting dogs because they are now primarily kept as pets.

As a result of what is now known in physics and chemistry, scientists have been able to make important discoveries in biology and medicine.

The practice of making excellent films based on rather obscure novels has been going on so long in the United States as to constitute a tradition.

Since the consumer considers the best fruit to be that which is the most attractive, the grower must provide products that satisfy the discerning eye.

Television the most pervasive and persuasive of modern technologies, marked by rapid change and growth, is moving into a new era, an era of extraordinary sophistication and versatility, which promises to reshape our lives and our world.

Television is more than just electronics; it is a means of expression, as well as a vehicle for communication, and as such becomes a powerful tool for reaching other human beings.
Even more shocking is the fact that the number and rate of imprisonment have more than doubled over the past twenty years, and recidivism — that is the rate for re-arrest — is more than 60 percent.

His teaching began at the Massachusetts Institute of Technology, but William Rainey Harper lured him to the new University of Chicago, where he remained officially for exactly a generation and where his students in advanced composition found him terrifyingly frigid in the classroom, but sympathetic and understanding in their personal conferences.

The sloth pays such little attention to its personal hygiene that green algae grow on its coarse hair and communities of a parasitic moth live in the depths of its coat producing caterpillars which graze on its mouldy hair. Its muscles are such that it is quits incapable of moving at a speed of over a kilo-meter per hour even over the shortest distances and the swiftest movement it can make is a sweep of its hooked arm.

Artificial flowers are used for scientific as well as for decorative purposes. They are made from a variety of materials, such as wax and glass, so skill-fully that they can scarcely be distinguished from natural flowers.

Three years of research at an abandoned coal mine in Argonne, Illinois, have resulted in findings that scientists believe can help reclaim thousands of mine disposal sites that scar the coal-rich regions of the United States.
When the persuading and the planning for the western railroads had finally been completed, the really challenging task remained: the dangerous, sweaty, backbreaking, brawling business of actually building the lines.

Because of the space crunch, the Art Museum has become increasingly cautious in considering acquisitions and donations of art, in some cases, passing up opportunities to strengthen is collections.

The United States Constitution requires that President be a natural-born citizen, thirty-five years of age or older, who has lived in the United States for a minimum of fourteen years.

Arid regions in the southwestern United States have become increasingly inviting playgrounds, for the growing number of recreation seekers, who own vehicles such as motorcycles or powered trail bikes, and indulge in hill-climbing contests or in caving new trails in the desert.

Stone does decay, and so tools of long ago have remained, when even the bones of the man who made them have disappeared without a trace.

Insects would make it impossible for us to live in the world; they would devour all our crops and kill our flocks and herds, if it were not for the protection we get from insect-eating animals.

It is true that during their explorations, they often faced difficulties and dangers of the most perilous nature, equipped in a manner which would make a modern climber shudder at the thought, but they did not go out of their way to court such excitement.

There is only one difference between an old man and a young one:
the young man has a glorious future before him an old one has a splendid future behind him: and maybe that is where the rub is.

I find young people exciting. They have an air of freedom, and they have not a dreary commitment to mean ambitions or love comfort. They are not anxious social climbers, and they have no devotion to material things.

I am always amazed when I hear people saying that sport creates goodwill between the nations and that if only the common peoples of the world could meet one another at football or cricket, they would have no inclination to meet on the battlefield.

It is impossible to say simply for the fun and exercise:
as soon as the question of prestige arises, as soon as you feel that you and some larger unit will be disgraced if you lose, the most savage combative instincts are around.

It has been found that certain bats emit squeaks and by receiving the echoes, they can locate and steer clear of obstacles — or locate flying insects on which they feed. This echolocation in bats is often compared with radar, the principle of which is similar.

As the time and cost of making a chip, drop to a few days and a few hundred dollars, engineers may soon be free to let their imaginations soar, without being penalized by expensive failure.