In America, it is not polite to telephone someone very early in the morning. The time of the call shows that the matter is very ______ and requires quick reply. It is the same to ______ telephone calls after 11 p. m. If someone receives a call during sleeping hours, he thinks its a matter of life and ______. The time chosen for the call communicates its importance.

In social life, time ______ a very important part. In America, guests may ______ that they are not highly respected (尊重) if they get the invitation to a dinner party only three or four days before the party date. But it is not the ______ in a countries. In other parts of the world, it maybe ______ foolish to make an appointment too early because it is easy to be forgotten.

The ______ of time is different in different parts of the world. So misunderstandings happen between people from cultures that treat time differently. To be on time is valued ______ in American life. For example, if people are not on time, others may think they are impolite. In the United States, no one would keep a business partner ______ an hour because it would be too impolite. A person who is five minutes late will say a few words of explanation to show his apology.

Everyone in business has been told that success is all about attracting and retaining (留住) customers. It sounds simple and achievable. But, in reality, words of wisdom are soon forgotten. Once companies have attracted customers they often ________ the second half of the story. In the excitement of beating off the competition, negotiating prices, securing orders, and delivering the product, managers tend to become carried away. They forget what they regard as the boring side of business —________ that the customer remains a customer. 

________ to concentrate on retaining as well as attracting customers costs businesses huge amounts of money annually. It has been estimated that the average company loses between 10 and 30 percent of its customers every year. In constantly changing markets, this is not surprising. What is surprising is the fact that few companies have any idea how many customers they have lost. 

Only now are organisations beginning to wake up to these lost opportunities and calculate the________ implications. Cutting down the number of customers a company loses can make a big ________ in its performance. Research in the US found that a five percent decrease in the number of defecting (流失的) customers led to profit increases of between 25 and 85 percent. 

In the US, Domino’s Pizza estimates that a regular customer is worth more than $5,000 over ten years. A customer who receives a poor quality product or service on their first visit and as a result never returns, is losing the company thousands of dollars in ________ profits (more if you consider how many people they are likely to tell about their bad experience). 

The logic behind cultivating customer ________ is impossible to deny. “In practice most companies’ marketing effort is focused on getting customers, with little attention paid to ________ them”, says Adrian Payne of Cornfield University’s School of Management. “Research suggests that there is a close relationship between retaining customers and making profits. ________ customers tend to buy more, are predictable and usually cost less to service than new customers. Furthermore, they tend to be less price ________, and may provide free word-of-mouth advertising. Retaining customers also makes it difficult for competitors to enter a market or increase their share of a market.”

Nothing seems more inevitable than aging and death ---- not even taxes. Every plant, animal and person you have ever seen will _________ die. But some recent research suggests that aging as we know it may not be inevitable. Indeed, as our _________ of it grows, aging can be viewed not as an unchangeable reality from which there is no escape, but as the product of biological processes that we may be able to _________ someday.

We already know that some animals do not seem to age. Many cold-water ocean fish and some amphibians (两栖动物) never _________ a fixed size; they continue to grow bigger, to be able to reproduce and to live until something kills them. What these _________ seem to be telling us is that something in their genes ---- and possibly in ours ---- controls the _________ of aging, and that aging is not the fate of every living thing.

_________ the history of life on earth, one of the most common difficulties that animals (and their cells) have faced has been a lack of food. About 70 years ago, scientists discovered that when animals are forced to live on 30 to 40 percent fewer calories than they would _________ eat, something unusual happens: they become _________ to most age-related diseases ---- cancer, heart disease, diabetes (糖尿病) ---- and live 30 to 50 percent longer. Restricting calories __________ aging. But what are the __________ genes that preserve vitality( 生命力 ) and starve off（抑制） diseases?

About 15 years ago, armed with powerful new molecular-research techniques, a few scientists began to __________ these genetic phenomena. They have discovered that a gene called Sir2 ---- which is present in all animals, including humans ---- is __________ for the health benefits of calorie restriction, perhaps by repairing our DNA. But if we had to restrict our calorie intake by 30 to 40 percent, would it be of any __________ use? Few of us would be capable of restricting our diets so severely that we were constantly __________ : whether or not it made life longer, it would surely make life feel longer.