We can see how the product life cycle works by looking at the introduction of instant coffee. When it was introduced, most people did not like it as much as 'regular' coffee and it took several years to gain general acceptance (introduction stage). At one point, though, instant coffee grew rapidly in popularity and many brands were introduced (stage of rapid growth). After a while people became attached to one brand and sales leveled off (stage of maturity). Sales went into a slight decline when freeze-dried coffees were introduced (stage of decline). The importance of the product life cycle to marketers is this: different stages in the product life cycle call for different strategies. The goal is to extend product life so that sales and profits do not decline. One strategy is called market modification. It means that marketing managers look for new users and market sections. Do you know, for example, that the backpacks that so many students carry today were originally designed for the military? Market modification also means searching for increased usage among present customers or going for a different market, such as senior citizens. A marketer may re-position the product to appeal to new market sections. Another product extension strategy is called product modification. It involves changing product quality, features, or style to attract new users or more usage from present users. American auto manufacturers are using quality improvement as one way to recapture（夺回） world markets. Note, also, how auto manufacturers once changed styles dramatically from year to year to keep demand from falling. 46. According to the passage, when people grow accustomed to one particular brand of a product, its            sales will ______. A. decrease gradually                                 B. become unstable C. improve enormously                            D. remain at the same level 47. The first paragraph tells us that a new product is _____ . A. usually introduced to satisfy different tastes B. often more expensive than old ones C. often inferior to old ones at first D. not easily accepted by the public 48. Marketers need to know which of the four stages a product is in so as to _____ . A. work out marketing policies                   B. promote its production C. increase its popularity                                      D. speed up its life cycle 49. The author mentions the example of 'backpacks'(Line 4, Para.2 ) to show the importance of             _______ . A. increasing usage among students       B. pleasing the young as well as the old C. exploring new market sections             D. serving both military and civil needs 50. In order to recover their share of the world market, U.S. auto makers are _______ . A. improving product feature                     B. making their products better C. modernizing product style                    D. increasing product quantity