One bag, that's it.

The importance of packing light cannot be overemphasized(过度强调). Limit yourself to 20 pounds in a carry-on bag. A 9'× 22' ×14' bag fits under most airplane seats. And after you enjoy that sweet mobility and freedom, you'll never go any other way.
You'll walk with your luggage(行李) more than you think you will. Before leaving home, give yourself a test. Pack up completely, and practice being a tourist for an hour. Fully loaded, you should enjoy window-shopping. If you can't, go home and thin things out.
Packing light isn't just about the trip over and back—it's about your traveling lifestyle. Too much luggage marks you as a typical tourist. It slams the back door shut. Changing locations becomes an important operation. With only one bag, you're mobile and in control. Take this piece of advice seriously. Pack light, and pack smart. These days, you can't bring anything possibly dangerous—such as knives, lighters or large amounts of liquid (液体)—in your bag.
What to bring?
How do you fit a whole trip's worth of luggage into a small backpack or suitcase(衣箱)? The answer is simple: bring very little.
Bring out everything you think you might need on the floor. Pick up one item(件) at a time and check it. Ask yourself—not "Will I use it?", but—"Will I use it enough to feel good about carrying it all the way? The world is getting really small—you can buy Colgate toothpaste, Nivea cream and Gillette razors in almost every country.
Think about what you can do without—not what will be convenient on your trip. When in doubt, leave it out.

    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.

    In many English homes people eat four meals a day: breakfast, lunch, tea and dinner. People have breakfast at any time from seven to nine in the morning. They eat porridge，eggs or bread. English people drink tea or coffee at breakfast. Lunch comes at one o'clock. Afternoon tea is from four to five in the afternoon and dinner is about half past seven. First they have soups, and then they have meat or fish with vegetables. After that they eat some other things, like bananas，apples or oranges. But not all English people eat like that. Some of them have their dinner in the middle of the day. Their meals are breakfast, dinner, tea and supper and all these meals are very necessary.

    American people like to say "Thank you when others help them or say something kind to them. People of many countries do so too. It is a very good habit.

    You should say "thank you "when someone passes you the salt on the table, when someone walking ahead of you keeps the door open for you, when someone says you have done your work well, or you have bought a nice thing, or your city is very beautiful. "Thank you" is used not only between friends, but also between parents and children, brothers and sisters.

    "Excuse me" is another short sentence they use. When you hear someone say so behind you, you know that somebody wants to walk past you without touching you. It's not polite to break others when they are talking. If you want to speak to one of them say.

    "Excuse me" first, and then begin talking. You should also do so when you begin to cough or make any noise before others.

    Let's learn to say "Thank you" and" Excuse me.

Nature is amazing! Take a close look at the world of insects, and you'll discover many unbelievable things. Consider butterflies (蝴蝶), for example. They have beautiful wings and magical flying skills. On summer days, you always see them flying freely over flower gardens and wild fields.

But did you know how butterflies become the flying insects? It is one of the wonders of nature. In the beginning, the mother lays a small and colourful egg on a leaf or stem of a plant. It is hard to believe that the egg will become something completely different in a few days. It becomes a walking insect. This insect is called a caterpillar. It now has legs, eyes and a large body. A new life begins. The caterpillar can eat, walk and see. But it is still not a butterfly.

Soon, after growing big, the caterpillar makes a cover for itself. It covers itself in the nice protective blanket (保护层) and goes to sleep. This is known as the "pupa (蛹)" stage. After some time, the blanket breaks and a wet butterfly appears. It now has six legs, a mouth, eyes and wings. Shortly, the beautiful butterfly spreads (张开) its wings and flies away. After a few weeks, this butterfly lays her eggs, and the cycle (循环) begins all over again.

This is just one example of the wonders of nature. Look around the natural world, and you will learn many truly amazing things.