Zu Chongzhi was a Chinese _______, astronomer and mechanic. He was born in to a well-educated family. _______ an excellent engineer, Zu Chongzhi’s grandfather taught him science. From an early age, ZuChongzhi showed great intelligence and curiosity, with special interest in mathematics and _______. Today we know Zu Chongzhi because he was the first person to _______ that pi falls between 3. 1415926 and 3. 1425927, and his result remained _______ value in the world for more than 900 years. He also worked out the close value of pi to be 355/113, which he called “close ratio”. This ratio was _______ hard that a Japanese mathematician named it “Zu’s ratio”.

It is not clear how Zu Chongzhi became interested in finding the value of pi, yet people have told stories about him. For a long time in the past, people believed that a circle’s circumference（周长）was _______ its diameter（直径）. Zu Chongzhi was not sure about this result and wanted to prove it _______. He used a _______ to measure the circumference of a wheel. Then he folded the rope into three equal parts and compared it with the diameter of ________. No matter how many wheels he measured, the diameter of the wheel was always shorter than a third of the circumference.

There are many inventions in the world. They are great and useful. The first great invention is the wheel and it is still widely used today. It is useful because it makes travelling long distances easier.

In the early 1800s, the world started to change. There was little unknown land in the world, but people needed to live, so they began to work to make the life better.

In the 19th century, people made many great inventions. The camera and the light bulb were among them. There were more great inventions in the early 20th century, such as helicopters in 1907, movies with sound in 1910 and jet planes in the 1930s. This was also a time when a new material （布料）was first made. Nylon （尼龙）came out in 1935. It changed the kind of clothes people wore.

By that time most people had had a very good life. Humans had a desire to know more. So they began looking for ways to go into space. Russia made the first step. Since then other countries, including the United States and China, have made their steps into space. In 1969, humans took the biggest step. An American first walked on the Moon. This was certainly just a beginning.

There will be more and more new inventions in the future and they will someday allow us to do things we have never dreamed of doing.

Six hours of walking in space. On August 20, Chinese astronauts Liu Boming and Nie Haisheng did the second spacewalk of the Shenzhou XII mission （任务）. They set up equipment （设备）and lifted a camera outside the Tiangong space station.

Spacewalks can be dangerous. There is no air in space, of course. And it’s filled with harmful radiation（辐射）. But the spacesuits,   although they are bulky（臃肿的）, can protect astronauts.

A spacesuit is like a small space station. It has everything astronauts need when they carry out a spacewalk. For example, China’s Feitian spacesuits have six layers（层）. The innermost（最里面的）layer collects astronauts’ urine （尿液）. There are four layers that help control the temperature and air pressure inside the suit. Spacesuits are filled with air, so they look like they’re puffed up. The sixth layer is made of special fibers（纤维）that protect astronauts from radiation.

Astronauts are connected to the space station with safety ropes. The suit has headphones and speakers for astronauts to communicate. There is also a mirror on the wrist （手腕）. Astronauts can check their suits by looking at it.

The first Feitian suit was made in 2008. Zhai Zhigang wore it to carry out China’s first spacewalk for about 19 minutes. The suits Chinese astronauts wear today are the second generation（代）of Feitian. It can support walks as long as eight hours and can be used more often. The first generation could only be used five times within two years, while the second generation can be used 15 times within three years. Each suit costs around 30 million yuan and it takes four months to make just one.

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When I was a little child, my parents took me to Germany.     26     When I came back, I could speak German fluently.

During a holiday, I stayed at home with nothing to do. My father brought a German book. “Why don’t you translate it into Chinese? It will be better than playing computer games all day.” said my father.     27     I promised to do 4, 000 words each day, but soon I found it hard to keep the promise. After translating only three pages, I already lost interest in the book.     28     I didn’t want to continue. I counted the words again and again. I felt as if two people were fighting in my mind. One said, “Don’t give up. Keep working hard and you will do well.” The other one said, “    29     It will be more interesting than translating.” I stood up and was about to start playing the games, but then I remembered what my parents had told me.

“Whatever you do, don’t stop half way.”     30    

Good afternoon, parents and teachers. Thank you for     36     （attend）this meeting.

Last weekend, one of our     37     （student）went to hospital. The student played computer games on the Internet all day Saturday     38     stopping to drink, eat or sleep. Finally, he     39     （become）very ill.

Some students play computer games for too long. This is     40       serious problem. In the past, students used     41     （play）outside more often, but now they spent     42     （much）time in front of computers. This is bad for their health.

Tomorrow, we     43     （have）some experts here to talk to the students about the bad effects of playing computer games. They’ll also give some advice on     44     to use computers for studying.

I hope we can all work together to stop students from spending too much time     45     （sit）in front of computers. Thank you for your time.