You might think that hamburgers were invented in the United States, but that is not totally true. These{{U}} (1) {{/U}}, or patties, actually came from Germany in the middle of the nineteenth century. They were brought to the United States by{{U}} (2) {{/U}}who came from the city of Hamburg. That is why{{U}} (3) {{/U}}was "hamburger steak".
However, people in other places{{U}} (4) {{/U}}that they invented the hamburger. Perhaps we'll never have a{{U}} (5) {{/U}}. But there's no question that the hamburger was a{{U}} (6) {{/U}}. Why? Perhaps because at that time, industry was growing and a kind of{{U}} (7) {{/U}}food was needed for workers.
The hamburger became even more popular{{U}} (8) {{/U}}when the first chain of fast food restaurants was started. This chain was called "White Castle". It served tiny hamburgers that were sold for only{{U}} (9) {{/U}}. Then, in the 1930s there came the{{U}} (10) {{/U}}where customers were served in their cars by waiters in uniform. And the hamburger was one of the most{{U}} (11) {{/U}}.
By now, The hamburger was ready to{{U}} (12) {{/U}}the world. And this happened with McDonald's, which was actually a{{U}} (13) {{/U}}at first. But by the early 1950s the hot dog was replaced by the hamburger. McDonald's and other fast food restaurants{{U}} (14) {{/U}}around the world throughout the rest of the twentieth century. McDonald's alone has{{U}} (15) {{/U}}for everyone person in the world.
The importance of the hamburger to{{U}} (16) {{/U}}remains significant. About{{U}} (17) {{/U}}of all sandwiches that are eaten are hamburgers. According to some sources, {{U}}(18) {{/U}}of current workers in the United States had their first job at McDonald's. But the face of the hamburger is changing{{U}} (19) {{/U}}. Nowadays it is possible to buy a chicken burger, a turkey burger, {{U}}(20) {{/U}}, or veggie burger.