1 . A satellite is an object in space that orbits around another. It has two kinds — natural satellites and artificial satellites. The moon is a natural satellite that moves around the earth while artificial satellites are those made by man.

Despite their widespread impact on daily life, artificial satellites mainly depend on different complicated makeups. On the outside, they may look like a wheel, equipped with solar panels or sails. Inside, the satellites contain mission-specific scientific instruments, which include whatever tools the satellites need to perform their work. Among them, high-resolution cameras and communication electronics are typical ones. Besides, the part that carries the load and holds all the parts together is called the bus.

Artificial satellites operate in a systematic way just like humans. Computers function as the satellite’s brain, which receive information, interpret it, and send messages back to the earth. Advanced digital cameras serve as the satellite’s eyes. Sensors are other important parts that not only recognize light, heat, and gases, but also record changes in what is being observed. Radios on the satellite send information back to the earth. Solar panels provide electrical power for the computers and other equipment, as well as the power to move the satellite forward.

Artificial satellites use gravity to stay in their orbits. Earth’s gravity pulls everything toward the center of the planet. To stay in the earth’s orbit, the speed of a satellite must adjust to the tiniest changes in the pull of gravity. The satellite’s speed works against earth’s gravity just enough so that it doesn’t go speeding into space or falling back to the earth.

Rockets carry satellites to different types and heights of orbits, based on the tasks they need to perform. Satellites closer to the earth are in low-earth orbit, which can be 200-500 miles high. The closer to the earth, the stronger the gravity is. Therefore, these satellites must travel at about 17,000 miles per hour to keep from falling back to the earth, while higher-orbiting satellites can travel more slowly.

2 . Parkinson’s is a progressive brain disease which leads to shaky hands and slow movement, and there is no cure. Tai Chi, a traditional Chinese martial art that combines (结合) slow, gentle movements with deep breathing and relaxation, may be an effective means of reducing the suffering. Recently, the researchers say that those who practised the martial art twice a week had fewer complications (并发症) and better quality of life than those who didn’t. Experts say the findings back up previous studies on the benefits of exercise for those with Parkinson’s.

The study, from Shanghai Jiao Tong University School of Medicine, monitored the health of hundreds of Parkinson’s patients for up to five years. One group of 147 people practised regular Tai Chi while another group of 187 did not. The researchers found that the disease progressed more slowly in the Tai Chi group on measurements of symptoms (症状), movement and balance. This group also saw fewer falls, less back pain and dizziness, with memory and concentration problems also lower than in the other group. At the same time, sleep and quality of life continuously improved.

Prof. Alastair Noyce, professor in neurology and neuroepidemiology at Queen Mary University of London, called it “an important study”—the positive effects on aspects of motor (运动的) and non-motor functions are impressive — but said there were limitations in its design, and more tests were needed.

“We already recommend Tai Chi, as well as other forms of exercise, but understanding which forms of exercise are most beneficial is an important goal to improve the long-term management of patients,” he said.

5 . Nowadays, it is common to see people wearing Hanfu, the traditional clothing of the Han ethnic group, at parks and attractions. More and more people are falling in love with Hanfu culture. The development of Hanfu culture has witnessed (见证) numerous changes in recent years and is taking on various forms.

Zhang Xiaomin has been a fan of Hanfu for five years now. Thanks to the popularity of social media, she can easily learn the latest trends and knowledge about Hanfu online now. “People used to only collect or appreciate Hanfu privately,” Zhang said. “But now it has moved to the mass market.” In the past, many people had the misunderstanding that “Han” refers to the Han Dynasty. Now more people are knowledgeable about Hanfu, and even expert in distinguishing (区分) the differences in Hanfu from different dynasties.

Miss Tang has also noticed a similar change. “Fans have become particular about the design and style of Hanfu,” Miss Tang said. “For advanced hobbyists, those seemingly fairy-like Hanfu dresses are not enough, since this style has been adapted to meet the tastes of the masses. They care more about how original Hanfu style are, like Quju (曲裾) and Mamianqun or ‘horse-face skirts’, which look more serious and complicated.”

The development of Hanfu has also triggered (引发) different events. You Gancheng has been in Hanfu circles for 13 years. “The Hanfu festival that a museum held in April offered many interesting activities like lectures, ceremonies, concerts and fairs,” she said. “Hanfu culture weeks, festivals and academic forums all provide platforms for fans to communicate.”

The rise of Hanfu culture also means the birth of an emerging business. Miss Cang has been running a Hanfu store for four years. The store provides Hanfu rental and photography services. “Many international schools now come to us for Hanfu events on traditional holidays,” Miss Cang said. Her store also actively participates in Hanfu festivals. “We often run a stand in Hanfu fairs, selling and displaying Hanfu we’ve designed. Sometimes we even provide Hanfu as prizes for competitions,” she said.

8 . A week before Christmas, my grandmother passed away. My boss _______ gave me several days off to go home for the funeral (葬礼) in Nova Scotia. I planned to leave on the 20th so that I could get home ______ to help my mother with both the funeral preparations and the preparations for a very ______ and busy Christmas.

Here, my string (一串) of bad luck began: my plan was ______ by a big storm, and I had to ______ a ferry (渡船) ticket for the 22nd, the last day that the ferry would run. I left as the roads were still ______, and I was two-thirds of the way through the long drive when my car ______. I pulled over and found, although I had a ______ tire (轮胎), I didn’t actually know how to ______ it. And it was snowing; I was so anxious that I almost ______. Just then a car stopped nearby. A lady came out and asked whether I was asking for ______. I told her I had to go home ______ for my grandmother’s funeral, but I had a flat tire and I would ______ my ferry. After hearing what I said, the lady took out her ______ and quickly helped me put on my tire at no charge! I was filled with ______. Thanks to her ______, I was able to catch the very last ferry, _______me hours of driving.

The woman is a stranger, ______ she tried her best to help me get home — even enough for me to give a hand to my mom and say goodbye to the dead. I’ll never ______ the kind stranger, who made a hard Christmas a lot easier, for both me and my family. I ______ the world is beautiful because there are lots of kind people in it.

9 . According to scientists, some tomatoes grown indoors are now just as flavorful as the ones grown outdoors in perfect summer conditions. There has been a lot of research and investment (投资) in hydroponic (水栽的) greenhouses, which allow farmers to grow tomatoes without soil, in recent years as consumers have needed more and better fresh vegetables year-round. “There’s a lot of techniques you can use to grow tomatoes off-season,” says Neil Mattson, co-director of Cornell University’s Controlled Environment Agriculture program. In the past five years, greenhouse tomato production has doubled.

That doesn’t mean all the tomatoes currently being grown in greenhouses are very flavorful. Flavor sometimes gets sacrificed for high yields   (产量), just as it does in the production of commercial field-grown tomatoes. “The greenhouse is such an expensive structure that we’re paying a lot to heat and light,” Mattson says. Therefore, farmers often need to grow a lot of tomatoes to make up for it. “And just like the field-grown varieties, much greenhouse-grown fruit is harvested before its peak (顶峰) and travels long distances before it ends up in a supermarket,” he says.

But that’s all changing with the new hydroponic system. Researchers are now trying their best to save some ripening (成熟的) time by growing produce locally. Gotham Greens, based in New York City, grows hydroponic tomatoes year-round and sells them to local restaurants and supermarkets. And Backyard Farms, based in Maine, supplies its hydroponically grown crop to nearby markets in the Northeast.

“It’s becoming increasingly important now that global warming is making outdoor farming less predictable (可预料的) , but greenhouse growers don’t have to worry about a heavy rain or a cold day destroying their fruit,” says Gene Giacomelli, who directs the Controlled Environment Agriculture Center at the University of Arizona. The advantages of a greenhouse are that growers can control the amount of heat and light their crops get. Many are equipped with man-made lights that growers can turn on when sunlight is not enough. And the hydroponic system allows them to control pretty much everything else.

“That’s not to say we’ll value the summer harvest any less. In the end, I still love growing my own tomatoes in my backyard in the summer,” Mattson says. “It’s psychological (心理的) ,but I think they taste best.”