What’s the most popular school for American students? The answer is the school dance. Most American high schools have at least two dances during the year, one in winter and the other in spring. Students take part in these dances because it’s a great chance for them to meet new friends and to be sociable（好交际的）. At the school dance, students are from all grades and classes.

Can all students attend the school dance? The answer is “No”. At the school dance, there will be strict rules to help create a healthy and enjoyable evening for the students. Most schools only accept dancers under 21 years old. In order to create a safe environment, all the dancers will be given a check before they come into the dance area. This is acceptable（可接受的）. But some rules may be a little bit over the top. For example, a school once asked its students to keep a standing position while they were dancing. As a “result”, the students didn’t have the chance of showing their cool dancing skills. However, you’d better not break the rules, or you’ll be asked to leave the dance floor, or even worse, but put on a “do not invite” list.

Jiaozi, also known as Chinese dumplings, is a popular food during holidays in Northern China. It has a long history in China.

Jiaozi is one of the most important foods in Chinese New Year. Since jiaozi is in the shape of old Chinese silver ingots（银锭）, it symbolizes wealth（象征着财富）. Traditionally, the members of a family get together to make dumplings on New Year’s evenings. They may hide something in one of the dumplings. They think it will bring good luck to the person who finds it.

As the Spring Festival means the start of a new year, people choose to eat jiaozi in the hope of having a good future in the coming new year.

When you have dumplings, you can make different kinds of Chinese jiaozi using different fillings（馅料）. There is no rule as to what makes dumpling fillings. They can be anything from vegetables, meat or seafood. Whatever the fillings are, the wrapping（包）skill needs to be exquisite（精美的）to make jiaozi good-looking.

As China is a country with vast territory（幅员辽阔）, there are differences in different areas in ways of making jiaozi or even serving it.

The International Space Station（ISS）, which goes around Earth, is the second brightest object in our night sky after the moon. In 1998, the first piece of the ISS was sent into space. Since then, 230 people from 18 countries have visited it.

Many countries have been working on space stations for years. Five space agencies—those of the United States, Russia, Canada, Japan and some countries in Europe—worked together to build it. China is not part of the ISS program, but it has helped with some of the station’s experiments.

The ISS holds three to six people at one time. Astronauts living there work on different science projects. The ISS has hosted over 1,500 such projects so far. 900 of those have been put into use in the science field.

But the station is out of its age. And it is coming to the end of its mission（使命）.In 2011, Russia said that the ISS would stop working in 2020 and it was becoming “space junk”. But the US later said it would use repairs to extend（延长）its service life to 2025.

The ISS costs $3-4 billion each year. Many have argued that the money could be better spent improving conditions on Earth.

“What will happen to the ISS after 2025 is unknown. There are lots of possible uses,”said Jeffrey Hoffman who ever worked in ISS. He is now a professor at a university. China will soon have its own space station, becoming the third country after Russia and the US to do so. The station is set to be finished around 2022. The ISS will retire（退役）, and Tiangong will be the only space station.