Everyone knows that the favorite food in the United States is the hamburger. It seems impossible, but people eat 34 billion hamburgers a year. This is enough to make a line of hamburgers around the world four times. The favorite place to buy hamburgers is a fast-food restaurant. In these restaurants, people order their food, wait just a few minutes, and carry it to their tables themselves. They can eat it in the restaurant or take the food out and eat it at home, at work, or in a park. At some restaurants people can drive up beside a window. They order the food, and a worker hands it to them through the window. Then they eat in their cars. Hamburgers are not the only kind of food that fast-food restaurants serve. Some serve fish, chicken, beef sandwiches, or Mexican food. They also serve fries, shakes (a drink made from milk and ice cream) , soft drinks and coffee. Fast-food restaurants are very popular because the service is fast and the food is inexpensive. For many people, this is more important than quality of the food. These restaurants are also popular because the food is always the same. People have known that if they eat at a company' s restaurant in the north or south of the city, the food will be the same. In a fast-food restaurant, people______.