1. Hot dog is a special sausage bread with hot smoked sausage in the middle, meson sauce and seasoning.

Hot dogs can be traced back to ancient Babylon. But it was introduced to America in the19th century. According to legend, shortly before the outbreak of the American Civil War, a man named Charles Faltman set up a food stall in new york, USA, selling smoked sausage rolls. Because this sausage roll is not only delicious, but also convenient to eat, it just caters to the fast-paced lifestyle of Americans, so it quickly spread to the United States. But at that time, this kind of food was not called "hot dog", but "Frankfurt". Later, one day in 1906, American sports cartoonist Tad Dorgan saw vendors selling this kind of food in new york baseball field. He found that it looked like a dachshund, so he improvised a cartoon: a bun with an exaggerated dog sausage, and the title was "hot dog". So this kind of food called "hot dog" is widely circulated in the United States and has become a very popular food.

Sandwich is a kind of sandwich bread, that is, some food (usually cold food) is sandwiched between two pieces of bread (usually buttered first), such as sauce, cheese, ham, roast beef, etc. They are called jam sandwich, cheese sandwich, ham sandwich and roast beef respectively.

There is a short story about the origin of "sandwich": It is said that in the18th century, there was a man named John montague IV, Earl of Sandwich in England. This man is a gambler and doesn't even want to leave the gambling table when eating. He just asked the servant to bring him two pieces of bread with meat and cheese to satisfy his hunger. Later, this way of eating was gradually accepted by people. People called this kind of food "sandwich", and this kind of food gradually became people's favorite food.

Hamburger used to refer to beef patties or steaks, but now it mainly refers to a kind of oblate beef patties bread. It is made by cutting beef into cakes and then cooking them in round rolls. But now when people (mainly in America) talk about hamburgers, they may also refer to beef patties or ground beef.

Hamburg can be traced back to medieval Europe. At that time, in order to be easy to digest, people chopped beef into patties before eating. Later, this food practice spread to Germany and became popular around Hamburg, so people called it "Hamburg". In the19th century, this kind of food spread to Britain and was further improved by the food producer Salisbury, so it became "Salisbury steak". /kloc-At the end of 0/9 and the beginning of the 20th century, this kind of food was introduced to America and was welcomed by people. But it's really popular in America. Around the 1920s, a snack chain named White Castle appeared in the United States. This chain store sells this kind of food at a very low price, which is called "hamburger" for short. Soon after, this delicious and cheap food became popular in America and became one of people's favorite foods.