Most people around the world are right-handed. This also seems to be true in history. In 1799, scientists studied works of art made at different times from 1,500 B.C. to the 1950s. Most of the people shown in these works are right-handed, so the scientists guessed that right-handedness has always been common through history. Today, only about 10% to 15% of the world's population is left-handed.

Why are there more right-handed people than left-handed ones? Scientists now know that a person's two hands each have their own jobs. For most people, the left hand is used to find things or hold things. The right hand is used to work with things. This is because of the different work of the two sides of the brain. The right side of the brain, which makes a person's hands and eyes work together, controls the left hand. The left side of the brain, which controls the right hand, is the centre for thinking and doing problems. These findings show that more artists should be left-handed, and studies have found that left-handedness is twice as common among artists as among people in other jobs.

No one really knows what makes a person become right-handed instead of left-handed. Scientists have found that almost 40% of the people become left-handed because their main brain is damaged when they are born. However, this doesn't happen to everyone, so scientists guess there must be another reason why people become left-handed. One idea is that people usually get right-handed from their parents. If a person does not receive the gene (基因) for right-handedness, he / she may become either right-handed or left-handed according to the chance and the people they work or live with.

Though right-handedness is more common than left-handedness, people no longer think left-handed people are strange or unusual. A long time ago, left-handed children were made to use their right hands like other children, but today they don't have to.

Bullet comments (弹幕) are a new form of comments (评论) which move across the screen while a video is playing in recent years. It's not only a way of communication but also serves as a bridge connecting people in the digital age. However, different people have different opinions about it. 

Mary did not understand such sentence as "She is blue today. ""You are yellow. ""He has a green thumb. ""He has told a little white lie. " and so on. And she went to her teacher for help. 

Mary: Mrs. Smith, there is a color in each of these sentences. What do they mean?

Mrs. Smith: In everyday English, Mary, blue sometimes means sad. Yellow means afraid. A person with a green thumb grows plants very well. And a white lie is not a bad one. 

Mary: Would you give me an example for "a white lie"?

Mrs. Smith: Certainly. Now I give you some cakes. In fact, you don't like it. What will you say?"

Mary: I will say "No, thanks. I'm not hungry. "

Mrs. Smith: That's a white lie. 

Mary: Oh, I see. Thank you very much. 

Hello, I'm Tom. I go to McDonald's farm today. There is a vegetable garden and a fruit garden on the farm. First I go to the vegetable garden. The potatoes are big and brown. The tomatoes are red, yellow and green. They are tasty (美味的). The green beans are so long and green. Then I go to the fruit garden. The watermelons are so big and sweet. The strawberries are red and sweet. But the grapes are green and small, they are not ready. There is an animal field, too. There are white horses and black horses. Look! Are those ducks? No, they aren't. They are hens. The hens are fat. I can see fourteen sheep over there. They baa and baa (咩咩叫) everywhere. The farm is so fun. I like it very much. 

Do you like living in a city? Look at the good sides. It is often easier to find work. And there is usually a choice (选择) of public transport (公共交通), so you don't need to own a car. Also, there are a lot of interesting things to do. For example, you can eat in good restaurants, pay a visit to museums and go to the theater and concert. What's more, when you want to relax, you can easily find a park to feed the ducks or just sit on the park bench and read a book. All in all, city life is full of interesting activities and you will never feel bored.

However, living in a city also has bad sides. For one thing, you must work hard and try to make as much money as you can. Because it is often very expensive to live in a city. Also, public transport is usually crowded, and even the parks can become full of people on Sundays. Besides, although there are many people in the city, it is still possible to feel lonely (孤独的).

I think young people like city life better because they love the excitement of the city and don't. mind the noise or the pollution.