“I can't see clearly, because I don't wear my glasses today.” We always hear people saying something like this. Glasses are very important to many people. Do you know how they were invented and developed?

    Glasses took a long time to develop into what you can find in the glasses store today. The Chinese first used colored glasses as fashion. They thought that those glasses had magic, but they didn't think that glasses could help eyes to see clearly.

    In 1262, the inventor, Roger Bacon, discovered the amazing function(功能) of lenses(镜片), and he thought that glasses could be used to help people to see. Twenty years later, in Florence, Italy, the inventor, Alessandro di Spina, made the first pair of glasses that could help people to see.

Although these glasses worked, scientists didn't understand how glasses helped eyes to see. They thought that eyes sent out light onto whatever a person was looking at, and then the light came back to the eyes. Johannes Kepler finally found out how glasses worked.

Inventors continued to improve glasses. In 1784, Ben Franklin created glasses that had bifocal(双焦的) lenses. Many years later, in 1827, George Airy made circle-shaped glasses to correct astigmatism, an eye problem that stops the eyes from seeing things clearly.

    The government in China ended his one-child policy and let families have two children instead in 2015.

    A Chinese Communist Party statement gave a number of reasons for the change in policy. The statement said the change is meant to balance population development, stop a falling birth rate(出生率)and strengthen the country's labor force(劳动力). China, with the largest population in the world, started the one-child policy in 1980. But the government allowed only a small number of couples to have two children. For example, some families in the countryside could have two children, if the first-born is a girl.

    In 2013, the Chinese government gave other couples a chance to have two children if one of them was an only child.

Jiang Quanbao, a teacher and population expert, explained how Chinese families react(反应) to the newest policy. "Too many young people in the cities are no longer interested in having a second child," he said. "People in the countryside are more interested. But some of them are already allowed to have two children." At the end of 2014, China had a population of 1.37 billion people. A total of 800 million of them have jobs. But the labor market need of labor by the year 2050. With the two-child policy, an increase in births can solve this problem.

    Boys and girls, what do you think of the two-child policy? Do you want to have a new-born brother or sister?

    If someone says to you: “give me five”, do not search your pocket to get five yuan! It will make others laugh! The person's not asking for your money, but your fingers. In the US, "give me five" or "give me the high five" is a popular gesture (动作). You can see it often in films or on TV. It means the clapping (拍) of each other's raised (举起的) right hands together.

    People do it when they meet for the first time or something happy happens. For example, a student has good marks in exams or wins a lottery ticket (彩票).If a football team wins a game, the players will give high fives to everyone around to celebrate.

    This gesture may come from the old Roman（罗马） gesture of raising the right arm for the emperor(皇帝). This showed that the person raising his arm did not have a sword (刀) in his hand.

Why not try to give the high five to your friends?