【正确答案】
The relationship between customer and seller is now becoming more and more important in people's life with the rapid development of market economy. A good relationship between customer and seller can make buying and selling a happy experience and benefit both buyer and seller.
A good relationship between customer and seller can only exist on the basis of honesty and respect. Sellers should be honest to customers, introducing the actual advantages and disadvantages of his goods. He mustn't deceive customers, charge too high a price, or serve them indifferently. On the customer's part, he should also respect the seller and be reasonable. Some customers think they are "God" to the sellers, so they often behave coldly or even rudely to them. That's not a good manner. As long as one buys of his own will, both sides are equal.
Sometimes problems and mistakes are inevitable. For example, the seller may forget to give his customer the change. If he doesn't do it on purpose, the customer should be considerate and excuse him. On the basis of honesty and kindness, problems can he resolved easily.

【答案解析】[解析] 文中开始段可阐明卖主与顾客的关系在现代生活中的重要性，中间段提出两者之间的良好关系必须靠诚实与尊重来维持，结束段说明遇到问题该如何处理，可举一例简要说明。