Flags have existed for over 3,000 years. The earliest flags were wooden or metal poles with a carving. About 2,000 years ago pieces of fabric were added to some poles for decoration. Over the next 500 years the free-flying part of the flag became more important.

    We all have ideas about what kinds of foods are good or bad to eat. As a result, people from one culture often think the foods that people from another culture eat are not accepted. Many people would find it terrible to eat mice, but there are forty-two different cultures whose people regard mice as proper food.

     Food likes and dislikes do not always seem related to nutrition. For example, broccoli is first on a list of the most nutritious common vegetables, but it is twenty-first on a list of vegetables that Americans like most to eat. Tomatoes are sixteenth on the list of most nutritious vegetables, but they are first on the list of vegetables that Americans like most to eat.

    But dislikes is not the only reason why some cultures will not eat a certain food. In some cultures, certain foods are taboo Taboo is a word from the language of the Fiji Islands that is used to describe something that is not allowed. We do not usually think about why certain things are taboo in our culture.

    One example is that Americans do not eat dogs, although people from some other cultures regard them as good food. In the United States, dogs are very important to people as pets. They are usually regarded as part of the family, almost like a child in some cases. What's more, dogs have value as protection against criminals. In fact, the dog's place in society as a company makes the dog taboo as food.Scientists believe that most food likes and dislikes are a result of the ways of life of different people. People will not eat pets such as dogs. Americans drink milk or eat a lot of beef because there is thousands of land for raising cows and their milk or meat can be shipped cheaply far away by train.

A

    People like to keep different animals such as dogs as pets. But cats are the most popular pets among Americans. So it is not surprising there are many expressions about cats. Do you know any of them? Now let me introduce some to you.

    Some cats like to catch small birds, like canaries. If someone looks very proud or pleased with himself, we say "he looks like the cat that ate the canary".

    Sometimes, a cat likes to play with a small animal it catches. So if you "play cat and mouse with someone", you keep him in a state (状态) of uncertain expectation. For example, a child might repeatedly give something sweet to her little brother, and then take it back when her brother is confused or relaxed.

    A cat will often catch a small animal and show it to its owner. The saying that "looks like something the cat dragged in(把……拖进来)" means something in bad condition.

    "A fat cat" is a person with a lot of money.

    There are many other expressions about cats in America. How interesting! Which kind of cat are you, or which kind would you like to be?