Question 24 is based on the passage you have just heard.

    Advertising informs consumers about the existence and benefits of products and services and attempts to persuade them to buy them. The best form of advertising is probably word-of-mouth advertising which occurs when people tell their friends about the benefits of products or services that they have purchased. Yet virtually no providers of goods or services rely on this alone, but use paid advertising instead. Indeed many organizations also use institutional or prestige advertising which is designed to build up their reputation rather than to sell particular products. Although large companies could easily set up their own advertising departments, write their own advertisements and buy media space themselves, they tend to use the services of large advertising agencies. These are likely to have more resources and more knowledge about all aspects of advertising and advertising media than a single company. It is also easier for a dissatisfied company to give its account to another agency than it would be to fire its own advertising staff. The client company generally gives the advertising agency an agreed budget, a statement of the objectives of the advertising campaign, known as a brief and an overall advertising strategy concerning the message to be communicated to the target customers. The agency creates advertisements and develops a media plan, specifying which media will be used and in which proportions. Agencies often produce alternative ads or commercials that are pre-tested in newspapers, television stations, etc., in different parts of the country before a final choice is made prior to a national campaign.

(24).How do large companies generally handle their advertising?

A)短文中提到，虽然对于大公司来说，建立自己的广告部门、自己撰写广告方案、购买媒体空间都不是多么困难的事情，但他们还是倾向于借助大型广告公司所提供的服务来做广告。