功能说明：广告的作用-The Role of Advertisement

广告的作用
【内容提示】
请用英语写一篇文章，从正面说明广告在现代社会中的作用。具体内容如下：
①广告是企业的喉舌。它可告诉人们关于厂家和产品的信息。
②广告在货物的流通中起着举足轻重的作用，它在厂家、商店和消费者之间架起了桥梁。
③广告可以刺激竞争，提高产品质量。
④广告可以创造大众需求，大众市场，从而支持了大批量生产，进而降低产品价格。
【作文示范】
The Role of Advertisement
Advertisement has been called “the voice of business”, for it announces new products and describes new uses and improved features of familiar ones. It seeks to make people know the things they need and to make them want to buy these things, and it tells what products or services are on the market, and how they can be obtained①.
The advertisement plays a vital② role in the spread-out and flow of goods. It puts up a bridge between factories or companies and shops, or stores and customers. Either side of them has no difficulty in finding cooperative partners.
Advertisements lead to improving products by stimulating competition③. Through advertisements, companies selling the same or similar products try to win each other for the attention of the buyers. The competition forces companies to improve their products so that people will buy them.
Advertisements can also lower the prices of products by creating the mass demand, or mass markets that help support mass production. Mass production lowers the costs of manufacturing④, and then the manufacturer can lower his selling prices. As a result, customers will buy commodities⑤ at cheap prices.
【词语解释】
①obtain[+b＇tein] v．获得；得到
②vital[＇vaitl] a．极其重要的；必不可少的
③stimulate competition[＇stimjuleit ?k&mpi＇tiM+n] 刺激竞争
④manufacture[?m$nju＇f$ktM+] v．（大量）制造；加工
⑤commodity[k+＇m&d+ti] n．日用品；商品
【写法指要】
1）本文是讲广告功能的说明文。文章单刀直入、开门见山，没有引言段，直接写出了广告的四种作用。每段写一种功能，各段第一句均为主题句，支撑句 （supporting sentences）都用来展开各个主题句中的制约思想。第一段阐述“企业的喉舌”，第二段说明“在商品流通中的重要作用”，第三段写“通过刺激竞争改进产品质量”，第四段写“创造批量生产降低价格”。
2）第一段中“familiar ones”中的“ones”是代词的指称（reference）用法，它指代前面的“products”一词。这样做可以避免无表达力的重复（inexpressive repetition）。但是，“to buy these things”中的“things”则不能用代词“them”指称，否则会产生歧义（ambiguity）现象，读者搞不清“them”指的是上文的“things”还是“people”。
3）第一段中“it tells”中的代词“it”最好不要省掉，因为整个句子并列成分多，如果只用“tells”，句子开头的主语“It”离得太远，会使读者产生误解。