Advertising can be a service to the customer. This is true when advertisements give reliable information about the goods advertised. Such information is needed if the customer is to make a sensible choice when he buys. It is useful in that it lets him know of the kinds of goods in the shops. Printed advertisements do this job best. Customers can collect them and compare them. They can be taken along to shops and their claims can be checked against the actual goods in the shops. however, some advertisements are not very useful to the customer. Instead of helping him to satisfy his real needs, they set out to make him want things. They set out to create a need. These advertisements are cleverly done. The people who produce them understand our weaknesses. They set out to make us believe that what they advertise will make us cleverer, prettier and more handsome, if only we use it. Actually, it is our money they are after and we should be on guard. Some advertisements mislead customers by using part of the truth to suggest something false, and it is skillfully made to give that idea to the careless reader, listener or viewer. At its best advertising can be useful to the customer. At its worst it can mislead him. Many newspapers check on the goods for which the advertisements made claims. Most newspapers are very careful about the small advertisements, which try to sell goods directly to the readers by post. Many newspapers print information about this on their small advertisement pages. Advertising has become a very big business, and good firms in it do all they can to make sure it is conducted with some attention to truth. This is a help to the customer. But the best way is for customers to be on the lookout. It can be inferred from the passage that advertisements can be useful if they   _  .
how a long list of the goods advertised give true information about goods tell customers what to buy appear on TV and in newspapers at the same time