2023年英语专四考试教材辅导练习下面是我为大家整理的英语专四考试教材辅导练习,供大家参考。英语专四考试教材辅导练习1The birth of computers has brought with it a new set of opportunities for mischief and crime. Today, computers are easy to come by and many people know how computer technology 11 . More importantly, the growing use of computer networks can multi* the violation of security, making large numbers of people more vulnerable than would be the case if they were using 12 , stand-alone computers.Whats more, computer experts agree thatdespite recent widespread publicity-computer viruses are 13 one of the many computer security problems facing the nation.The U. S. Defense Advanced Research Project Agency has requested that the Research Councils Science and Technology Board 14 the security problems posed by computer technology, see what 15 may already exist, review research efforts 16 at avoiding security problems in the future, and evaluate existing policies 17 to computer security. The study committee will examine the 18 of security for a broad spectrum of users, including the business, national security, and academic communities, as well as the 19 public.David. Clark, senior research scientist, Laboratory for Computer Science, Massachusetts Institute of Technology, will chair the 20 of experts in electronic security, net-work security, computer law, software engineering ? and operating systems. The committee will also include computer users from the defense and banking industries.A. only B.works C.solutions D.generalE. issue F.fundamentally G.universal H.assessI. aimed J.single K.committee L.generatesM. relevant N.question O.community参考答案II. B 12. J 13. A 14. H 15. C 16. I 17. M 18. E 19. D 20. K英语专四考试教材辅导练习扩展阅读英语专四考试教材辅导练习（扩展1）最新公共英语考试教材辅导训练最新公共英语考试教材辅导训练1Repeats Repeats RepeatsIt takes a lot of investment in promotion, product design, operations, and lots of other stuff to attract and be ready to serve a new customer. Then, when you actually attract a new customer, you may have to educate him or her about your products, sales, and business policies. You may have to do a credit check, set up a new account for the new customer, create a new file with a new label just for that new customer, and gather lots of information about that customer in order to provide them with the service they expect.Add up all that effort, and you can see that adding a new customer to your business can take quite an investment in time, money, and energy. Business experts who study this kind of thing figure that it costs something like five times more to serve a new customer than a repeat customer.Here are two very important truths about why creating repeat customers through outstanding service is worth the trouble:1.Repeat=Lower ExpenseMost organizations spend much of their time and energy acquiring new customers. They advertise. Certainly, a business can grow by adding new customers. But it might be much more profitable by spending more energy encouraging existing customers to buy again and again.Heres why. Existing customers already know your company. They have an idea of what it stands for. They have sampled the quality of its merchandise. So it should cost far less-maybe even nothing-to encourage satisfied customers (you did satisfy them, didnt you?) to return time and again. To attract great masses of the uninitiated to try your company for the first time costs far more. They dont know about your business and they certainly dont care about it. So in order to get their attention and motivate them to give you a try, you often need to buy ads, send countless mailings, offer steep discounts, and increase sales compensation.Would you rather spend $10 on ads, mailings, special discounts and the like to attract a new customer for their first $50 purchase, or 50E to mail a customized reminder letter to your repeat customer who may well make two or three additional $50 purchases with nothing more expensive than some heartfelt words of encouragement and appreciation?2.Repeat=RevenueSupposing a customer goes every morning to the same convenience store for a large coffee. He spends about a dollar on it. To the clerk completing the transaction on any given morning, this is a $1 customer.But this same customer also makes a habit of returning at lunch and buying a prepared sandwich, a soda, and a snack for the afternoon, about a $6 transaction. Sometimes he brings his friends in the store and they each spend a few dollars for lunch, too. Then, on his way home at night, he often stops at the store for another cup of coffee and maybe picks up a half-gallon of milk.So in an average week, this “$1 cop of coffee customer” actually spends somewhere around $30 to $50 in that convenience store, not to mention whatever his buddies spend on their lunches. So in an average year, this $1 transaction guy is actually visiting the store two or three times a day, about four days out of the week, and d