Animals perform many useful and entertaining jobs. Dogs are particularly valuable in guiding the blind, protecting property, finding lost people, and hunting down criminals. Horses are used in guarding herds; carrying men in lands where there are no roads, and helping farmers work their land. Pigeons have long been used to carry messages. Wild animals from the jungles, forests and seas are very popular performers in circuses and movies. People realize that, although animals may not have the same intelligence as human beings, they are smart enough to learn certain things.

      Dogs are extremely useful as companions for blind people. When a dog has been properly trained, he will always lead his blind master in the right direction and keep him out of danger. For example, seeing-eye dogs learn never to cross a busy road when cars are coming, even if their masters command them to do so.

      Horses are also able to learn many things too. Horses that are used for guard or police duty must learn never to be frightened of noises, traffic, and other disturbance. Racing horses are able to run much faster than other horses, but they are also quite high strung. Therefore, it is necessary for people who train them to be very patient and understanding.

      Pigeons have a natural instinct to return home, even if they are very far away and the trip is hard or dangerous. Men utilize this homing instinct to send messages on small pieces of paper that are fastened to the pigeon's back or legs. In wartime, pigeons have been known to fly as fast as 75 miles an hour and to cover distances of 500 to 600 miles. These homing pigeons begin their training when they are about four weeks old. After a few weeks they can begin flying and carrying messages. If all goes well, their flying career lasts about four years.

      Animals can learn to do many things that, while not necessarily useful, are very amusing to watch. In circuses, animals are taught to do the tricks that are most compatible with their physical and temperamental make-up. Lions and tigers can be taught to leap and spring gracefully when told to do so, or to stay in place on command. Elephants learn to walk in line, to stand on their hind legs, to lie on their sides, and to stand on their head. They can also learn to dance.

21. complete an activity (Para. 1)

22. things that belong to someone (Para. 1)

23. protecting (Para. 1)

24. pieces of written information (Para. 1)

25. the ability to learn and understand (Para. 1)

26. persons or animals accompanying someone (Para. 2)

27. order (Para.2)

28. something that interrupts (Para. 3)

29. an innate behavior in response to certain stimuli (Para. 4)

30. make use of (Para.4)31. travel a certain distance (Para. 4)

32. continues for a particular length of time (Para. 4)

33. entertaining (Para. 5)

34. suitable (Para. 5)

35. relating to the emotional part of the character (of an animal) (Para. 5)

Paragraph Ten

There are 15 million of us who fly across multiple time zones every year, with 500,000 of us in the air at any given moment. And for those of us who fly more than a couple of time zones from home, jet lag can be a serious challenge.

Millions of people s___ from jet lag every year.

   Altogether, American consumers today owe about 1.3 trillion dollars.

      There is some danger in taking on debts, however. When the economy slackens and employers lay off workers, families that lose breadwinners often fail to make the payments on their debts. (46. If they fall behind too far on these responsibilities. they run the risk of having their houses, cars, or other items taken over or repossessed by the lenders).

      But in the U.S. economy, most people are lenders as well as borrowers. Normally a family has a saving account, money that is, in effect, loaned to a saving institution in return for interest. Most also have life insurance. The insurance company takes the premiums, guarantees a payment to be made when a policy-holder dies, and meanwhile invests some of the money.

      (47. Many experts recommend that families save no less than 5 percent of their disposable income for further needs.)

      Many countries depend much less than the U.S. does on the marketplace to decide who will sell goods and in what quantity. In communist and socialist countries, government agencies decide the amount, type and price of many of the goods to be produced. Many or all places of economic activity such as factories, farms, mines, utilities and transportation network are owned chiefly by the government.

      In the U.S., too, the role of government is growing. (48. Corporate leaders and economists are wondering how much regulation the market system can take before it loses its ability to respond to consumer needs.) But the system continues to function, and businesses continue to work for more profits and consumers for more income, knowing that they will be able to retain much of their wealth.

      (49. Most men and women learn early that society places a certain monetary value on various professions and skills, based again on the law of supply and demand.) Doctors, who must study long years to develop specialized skills and are therefore in short supply, earn more than labors who have little training and many competitions for the same job.

      That's not to say that good jobs and more wealth are guaranteed to Americans. The U.S. economy has been plagued periodically with two major problems: high unemployment and the rising cost of living—inflation.

      The two problems are closely linked. (50. When prices climb faster than people's incomes, families sooner or later are forced to cut back on buying in order to make each end meet.)

      (51. That limits what business can produce and how many people they can employ. It may even start a temporary decline in the country's economy—such as the one that ran from late 1973 to the spring of 1975, when millions of people were laid off from their jobs.)

      Still, despite all of the problems that exist, most Americans prefer the U.S. economic system to any other, as the result of poll after poll indicates.

Paragraph Seven

Many centuries of rain caused huge rivers to move violently through this area. Over time, these rivers cut deep into the new mountains. During the great Ice Age, millions of tons of ice cut and shaped the cooled granite to form giant rocks, known as Half Dome.

Various forms of water c____ the outlook of the area.

Paragraph Eight

New climate simulations from NASA show that under the warmer global temperatures of the 20th century, water vapor in the atmosphere took longer than normal to fall, out of the sky as rain, snow and other precipitation. Generally speaking, the amount decreased over land but increased over oceans.

Warmer weather p____ less rain on land but more at sea.

Paragraph Nine

To tell someone that they should lose a few 1bs — even if you are just trying to help — could actually cause them to gain weight instead, according to new research. The study showed that women who receive more “acceptance messages” are more successful at maintaining and even losing weight overall, compared to those who receive more negative messages.

Negative messages are not helpful for weight l____.

Paragraph Five

Dining out with little children can be frustrating. They are either running around the entire restaurant or refusing to eat their meal. But now a Maryland restaurant has created a menu that all parents will relate to because it translates phrases such as I don't know what I want and I'm not hungry into meals you can order for them.

A f____ menu for children.

Paragraph Six

Excessive pressure from schoolwork is probably the most common problem in urban areas affecting Chinese children's development. Giving children time to dabble' in many fields is vital for their physical and mental development. In the process, they will gradually show a liking for particular activities. Parents can help their kids make choices.

“Less work, more play" is g___ for the growth of children.

Paragraph Two

In the U.S. today, it is common to pay one fourth to one third of a family's income on the place to live. Big houses are more expensive than smaller ones. And houses closer to the center of big cities are more expensive than the ones in the suburbs or in small towns.

The high c___ of housing in the U.S. today.

Paragraph Four

Interview is always used to select candidates. The argument against it is that through interview, employers do not choose the best candidate, but the one who gives them a good first impression. The argument in favor of it is that an employer pays more attention to the suitability of candidates personality for the particular work situation.

Opposite o____ on interview.

Paragraph Three

Consumers of electricity usually accept the fact that power cuts frequently occur during thunderstorms. If outages occur on a sunny day, consumers will blame the power company. However, most outages occur due to circumstances beyond the power company's control. Animals with the ability to reach the top of power poles can knock out power of many houses.

Various c____ of power failure.