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It is difficult to imagine what life would be like without memory. The meanings of thousands of everyday perceptions, the bases for the decisions we make, and the roots of our habits and skills are to be found in our past experiences, which are brought into the present by memory.
Memory can be defined as the capacity to keep information available for later use. It includes not only “remembering“ things like arithmetic or historical facts, but also involving any change in the way an animal typically behaves. Memory is involved when a rat gives up eating grain because he has sniffed something suspicious in the grain pile. Memory is also involved when a six-year-old child learns to swing a baseball bat.
Memory exists not only in humans and animals but also in some physical objects and machines. Computers, for example, contain devices for storing data for later use. It is interesting to compare the memory-storage capacity of a computer with that of a human being. The instant-access memory of a large computer may hold up to 100, 000 “words“—ready for instant use. An average U. S. teenager probably recognizes the meaning of about 100, 000 words of English. However, this is but a fraction of the total amount of information which the teenager has stored. Consider, for example, the number of faces and places that the teenager can recognize on sight.
The use of words is the basis of the advanced problem-solving intelligence of human beings. A large part of a person’ s memory is in terms of words and combinations of words.
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No one knows how man learned to make words. Perhaps he began by making sounds like those made by animals. Perhaps he grunted like a pig when he lifted something heavy. Perhaps he made sounds like those he heard all round him—water splashing, bees humming, a stone falling to the ground. Somehow he learned to make words. As the centuries went by, he made more and more new words. This is what we mean by language.
People living in different countries made different kinds of words. Today there are about fifteen hundred different languages in the world. Each contains many thousands of words. A very large English dictionary, for example, contains four or five hundred thousand words. But we do not need all these. Only a few thousand words are used in everyday life.
The words you know are called your vocabulary. You should try to make your vocabulary bigger. Read as many books as you can. There are plenty of books written in easy English for you to read. You will enjoy them. When you meet a new word, find it in your dictionary. Your dictionary is your most useful book.
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Concerning money or anything else, conflicts between husband and wife usually reflect a power struggle. Conflicts between parent and child often centre around the same issue. As children enter adolescence , they begin to demand greater freedom to go where they please, do what they please, and make decisions without parental interference. Many American parents do not know how to deal with their teenagers and seek advice from books, lectures, and parent training courses. Parents want to maintain a friendly relationship with their teenagers and also want to guide them so that their behavior will be whatever the parents consider proper and constructive.
But in a society of rapidly changing social and moral values, parents and children often disagree about what is important and what is right.
Arguments may concern such unimportant matters as styles of dress or hairdos. But quarrels may also concern school work, after school jobs, decisions, use of the family car, dating, and sex behavior. Some families have serious problems with teenagers who drop out of school, run away from home, or use illegal drugs. Because so much publicity is given to the problem teenager, one gets the impression that all teenagers are troublemakers. Actually, relatively few adolescents do anything wrong, and nearly all grow up into “solid citizens“ who fulfill most of their parents’ expectations. In fact, recent studies show that the “generation gap“ is narrowing. The vast majority of teenagers share most of their parents’ values and ideas. Many parents feel that they get along with their adolescents quite well.
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The top of the world is a wonderland. In winter, the temperature often falls to -30°F and the sun never rises. The ocean is surrounded by frozen ground. There are few people or trees, but to polar bears, the Arctic is home.
Polar bears have thick fur, big paws and other features that make them well prepared for life in their tough environment. In fact, they need the Arctic sea ice for survival. But climate change is causing larger and larger areas of summer sea ice to melt. Experts say that if warming patterns continue, the Arctic could be free of summer sea ice by 2050. That may cause two-thirds of the word’ s 20, 000 polar bears to be gone by then too.
Polar bears can’ t survive for long on land. Seals are their main source of food. The only place where polar bears can hunt seals is on the ice. Although these bears are strong swimmers, they are no match for lightning swift seals in the water. A polar bear has brilliantly clever strategies to overcome this disadvantage. In winter the bear waits motionless beside a seal’ s breathing hole, which is a narrow tunnel through the ice. Often many hours pass before the seal comes up for air and the bear kills it with a powerful blow of its paw. In summer, the polar bears that live on land eat very little and wait for the sea ice to return.
With the sea ice forming later in the year and melting earlier, polar bears do not have enough opportunity to hunt and eat. Less sea ice makes it harder for the bears to catch the seals. The bears must swim longer distances between ice packs, and they can’ t always make it. The ice is also getting thinner. These conditions can cause polar-bear cubs to become separated from their mothers, who provide them with food.
Steven Amstrup is the chief scientist of Polar Bear International. The group aims to save the bears and their home. “The more people who see polar bears and understand their difficult situations, the better the chance we’ll alter our warming path in time to save them, “ he says.
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It seems very difficult______. to stop the child to cry restraining the child to cry to stop the child from crying holding the child’ s crying
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Fifty years ago, wealthy people liked hunting wild animals for fun______sightseeing. than to go rather than to go more than going other than going
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One car went too fast and______missed hitting another car. completely greatly narrowly little
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______today, he would get there by Friday. Were he leave Was he leaving Were he to leave If he leaves
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This is a nice car, but we cannot______it. provide afford supply manage
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Not only______be interesting to us, but also its language will help us in composition. the novel will will the novel is the novel the novel is
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To make up an objective test, the teacher writes a series of questions, ______has only one correct answer. some of which which each of which that
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Shortly after the accident, two______policemen came to the spot. dozen of dozens dozen dozens of
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Please let us have more time, ______? shall we will you won’ t you don’ t you
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______the fog, we should have reached our destination. Because of In spite of In case of But for
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______student with a little common sense should be able to answer the question. Each Either Any One
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At first the institute refused to purchase the telescope, but this decision was ______revised. occasionally consequently successively subsequently
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Please keep an eye on my luggage, and I’ll be back______. in time in no time at one time at a time
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They discussed the problem three or four times, but could come to no______. end conclusion result judgment
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Young______he is, he knows what is the right thing to do. that as although however
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Do you know why John didn’ t______at the party yesterday evening? show off show down show up show in
