The invention of telephone has greatly eased the communication among people，but callers should be careful about when to make a phone call or it will cause embarrassments.

It is not customary to telephone someone very early in the morning in the USA. If someone is called very early in the morning，while he is shaving or having breakfast，the time of the call indicates great importance of the matter which requires immediate attention of the person called. The same implication is attached to telephone calls made after 11:00 p.m. at night. If someone receives a call during sleeping hours，he assumes it’s an urgency of life or death. The time chosen for the call communicates its importance. Time plays a very important role in our social life as you can imagine. In the USA an invitation should be sent to the guests in advance because guests usually believe that they are not highly regarded if the invitation to a dinner party is extended only three or four days before the party date. But it is not always necessarily true of the case all over the world. In some other countries，it may be taken stupid to make an appointment too far in advance because plans made for a date more than a week away tend to be forgotten. The concept of time varies in different regions of the world. Thus，misunderstandings are sometimes inevitable between men of different cultural backgrounds that treat time differently. Promptness is valued highly in America，for example. A lack of promptness is regarded as being impolite or not being fully responsible. In the US it would be incredible to keep a business partner or a guest waiting for an hour，and it would be too impolite and unacceptable by their social etiquettes. A person who is 5 minutes late is expected to give some words of explanation to the people waiting，though he might not complete his sentence. 16. What is the main idea of this passage？ A. It is not customary to telephone someone in the morning or in sleeping hours in the US. B. The role of time in social life over the world.. C. If people are not prompt，they may be regarded as impolite or not fully responsible in the US. D. Not every country treats the concept of time as the same. 17. What does it mean according to the passage if you call someone during his or her sleeping hours？ A. A matter of work. B. A matter of life or death. C. You want to see him or her. D. You want to make an appointment with him or her. 18. Which of the following time is proper if you want to make an appointment with your friend？ A. At 7:00 a.m. B. At 4:00 p.m. C. At the midnight. D. At 4:00 a.m. 19. Which of the following statements is true according to the passage？ A. In the USA guests tend to feel they are highly regarded if the invitation to a dinner party is expended only three or four days before the party date. B. There id no misunderstanding between people from different cultures about the concept of time. C. It may be considered foolish to make an appointment well in advance in the USA. D. Being on time is highly valued in America. 20. From the passage we can infer that ____________. A. it’s a matter of life or death if you call someone in daytime B. the meaning of time differs in different parts of the world C. it makes no difference in the US whether you are early or late for a business party D. if a person is late for a date，he needn’t make any explanation