A、Because they like to keep them at home. B、Because they do not want to take the trouble to throw them away. C、Because they are

"Everybody loves bargain" is a well-known saying. A bargain is a good deal. It is something you get for less than its perceived value. One person’s useless, ugly, or broken object can be another person’s bargain. This is why so many Americans do not throw things away. They put them outside their house. They put up a "For Sale" sign. And, as simple as that, they have a yard sale.
   In some parts of the country, such a sale might be called a garage sale or a-moving sale. Whatever the name, the activity is the same. People sell things they no longer want.
   Over the years, many people’s houses fill up with objects, which are no longer useful to the owner. Yet it seems wasteful to throw them away. Often, people must sell the things they do not use anymore before they move to a different house.
   The sellers put a paid announcement in a local newspaper. It tells when and where the yard sale will take place. It lists some of the things to be sold. These sales are very popular during weekends in spring, summer and autumn.
   Early in the morning, all the things to be sold are carried out of the house. Then they sit all day in the sunlight-like tired guests at a party-waiting for someone to take them home.
   Just about anything can be sole at a yard sale. Sometimes, there are more clothes than anything else. Cooking equipment is also popular. So are old toys, tools, books, tables, and chairs. Then there are objects called "white elephants". A white elephant is something you think is extremely ugly or useless.
   Usually, the seller puts a price on each object at a yard sale. However, that price can almost always be negotiated.
   Serious buyers also spend time getting ready for yard sales. They collect newspaper announcements. Then they make lists of the sales they want to attend. Some use maps to plan their trip. Want to get to as many sales as possible.
   New things in stores cost more than some people can pay. So they are happy to find a painting. A warm coat or a chair for 10 or 15 dollars. Perhaps they find dishes for 20 dollars that would cost 100 dollars in a store.
   Some people go to yard sales to find a special thing they collect. They usually collect. They usually collect small objects like old money, stamps, dolls, bottles, baseball cards, toys and advertising signs.
   Most people who go to yard sales, however, are not looking for anything special. They might buy an object simply because it costs so little. They enjoy negotiating over prices, even if they really do not need the object. Later, they may hold their own yard sale to sell all the things have bought.
Questions:
15: Why many Americans do not throw things away?
16.What is Yard sale also called?
17.What are the popular things sold at a yard sale?
18.Which of the following statements is NOT true?