听力原文： Every couple who goes to the altar believes that they will make that trip only once in their lives. They want the day to be perfect, and they are asking for much more than good weather. Whey want the most beautiful clothes, the freshest flowers. Moreover, her family who will pay the bill is not in any mood to economize. A quick look at any bride magazine will reveal that plenty of attractive goods and services compete for a share of the wedding budget. Besides the obvious choices of tings, dresses, flowers, and photographs, there are the less apparent expenses: a big cake, a rehearsal dinner, a reception, music for both the ceremony and the reception, tips and even napkins and matchbooks printed with the couple's names and the wedding date. As the arrangements are generally complicated, there are plenty of services that can be hired to help with the planning and execution of every aspect of the wedding: planning the photographs, selecting the wedding rings, choosing the flowers, picking the honeymoon spot, and so on. One magazine lists over 350 such companies who have something to offer. Considering that weddings do more than 12 billion dollars worth of business annually in the U.S alone, it isn't surprising. What is surprising is that no one company dominates the industry. It seems that when people plan for a day as special to them as a wedding, they resist standardization. They turn instead to the small local suppliers known to them or to their friends. Family members or friends often serve as photographers, caterers and musicians. This not only helps bring the wedding cost down, but makes it more personal. What about the couple that doesn't want to take in this billion-dollar industry? They can go to city hall and get married for less than the price of a hamburger. Questions: 15.What does the expression 'the billion-dollar industry' refer to? 16.Which of the following is not mentioned? 17.Why is it true that not a single company can dominate the industry? 18.Which of the following isn't true according to the talk? (35)