【推荐1】When NASA astronaut William Shepherd and Russian cosmonauts Yuri Gidzenko and Sergei Krikalev entered the International Space Station on November 2, 2000, they became the first of many to live in the orbiting laboratory 227 nautical miles (海里)above Earth.

Since that first 136-day stay for Expedition 1, the space station has served as a center for continuous human occupation, scientific research and a proving ground for future space exploration for 20 years.

Early in the space station program, the main focus was on building the space station. After that was completed in 2011, the focus has changed to science. More than 3,000scientific investigations have been conducted on the space station. This research has extended to a great many subjects.

While the research conducted on the space station throws light on how a range of things react to the lack of gravity，it has also been used to improve our lives on Earth. Through experiments on the station，we've learned better ways to purify air and water in our homes, developed advance rents in telemedicine，and found better treatments for diseases like cancer.

The space station is also being used as a proving ground as NASA prepares to return humans to the moon by 2024 through its Artemis program, as well as a future human task to Mars.

Going forward, Shepherd believes that a trip to Mars or other locations in the solar system will require large vehicles that will require construction in orbit, using spacewalks and robotics. It will also require the work, expense and cooperation(合作) of several countries.

“If you look at the International Space Station, it's really a blueprint (蓝图) for how to do this.”

【推荐3】How can you find out what is going on inside a person’s body without opening the patient s body up? Regular X-rays can show a lot. CAT scans can show even more. They can give a complete view of body organs.

What is a CAT scan? CAT stands for a kind of machine. It is a special X-ray machine that gets a 360-degree picture of a small area of a patient’s body.

Doctors use X-rays to study and determine diseases and injuries within the body. X-rays can find a foreign object inside the body or take pictures of some inside organs to be X-rayed.

A CAT scanner，however，uses a group of X-rays to give a cross-sectional (横截面) view of a specific part of the body. A fine group of X-rays is scanned across the body and around the patient from many different directions. A computer studies the information from each direction and produces a clear cross-sectional picture on a screen. This picture is then photo-graphed for later use. Several cross sections, taken one after another，can give clear “photos” of the entire body or of any body organs. The latest CAT scanners can even give clear pictures of active，moving organs，just as a fast-action camera can “stop the action”，giving clear pictures of what appears unclear to the eye. And because of the 360-degree pictures, CAT scans show clear and complete views of organs in a manner that was once only shown during operation or examination of a dead patient.

Frequent appearance before X-rays can cause skin burns, cancer or other damage to the body. Yet CAT scans actually don’t cause the patient to more radiation than regular X-rays do. CAT scans can also be done without getting something harmful into the patient, so they are less risky than regular X-rays.

CAT scans provide exact, detailed information. They can quickly find such a thing as bleeding inside the brain. They are helping to save lives.

【推荐1】Social Media

Social media can be defined as web-based mobile media that are used for people to interact, connect and communicate with each other. It often involves the creation and sharing of content( writing, pictures and videos) that people make themselves, mostly through the Internet.

    1    The first type involves people getting together to work on a project, for example, Wikipedia. Blogs and microblogs (such as Twitter) are another type of social media. There are other websites like YouTube that allow people to share content such as pictures, articles or videos.     2    These sites allow people to stay in touch with friends, make new ones and join communities. Facebook is an example of this type. Many people like to play games on the Internet and, yes, there are social media games as well. These games allow gamers to interact with each other and play with or against other gamers. The popular game World of Warcraft is a good example. The final type of social media is websites like Second Life, where people can picture they are in the real world.     3    

Social media are different from traditional media. With social media, many individual people in different places create content. Another difference is that people who produce content in social media don't need very special skills.    4     It takes only a few minutes to write a twitter post, for example.

    5    But whatever you might think, social media is here to stay.

【推荐2】Nearly 25% of the entire U.S. population is likely to hit the road during the holidays this year. We’ve picked the best road food stops along some of the South’s most traveled interstates（洲际公路）.

1-35∣San Antonio, TX, to Oklahoma City, OK

Fancy That∣Exit 109, Norman, OK I Miles from Interestate:2.8

This downtown store offers a sit-down “classic lunch” for $8 that includes an entrée（主菜）and a side; a big meatball sandwich, perhaps, with a strawberry, blue cheese, or a fat BLT on Texas toast with a salad.

215 East Main Street: 236/908-2209; www.fancythat.us.com

Babe’s Chicken Dinner House Ⅰ Exit 477, Sanger, Texas Ⅰ Miles from Interstate: 0.8

You’ll find yourself at Babe’s by the log-foot-tall chicken standing outside the front door of this store. But here’s the real draw: golden fried chicken and chicken-fried steak, served worth family-style sides.

202 North Fourth Street: 116/498-1208; www. Babeschicken.com

I-40∣Nashville, TN, to Wilmington, NC

The Feed Bag Restaurant I Exit 174, Farmington, NC I Miles from Interstate: 2.2

Located in a former general store down a country road, this simple country restaurant serves fresh, local food with zero cheats and tricks.

2339 NC Highway 801 North; 336/998-1109

Sunrise Biscuit Kitchen I Exit 270, Chapel Hill, NC I Miles from Interstate: 1.8

Sunrise is sandwich king—there’s no beating these giant biscuits filled with egg, sausage, cheese, or whatever filling you’d like. It’s drive-through only—perfect for when you don’t have time to stop and sit. Just get there before 2:30 p.m. when they close.

1305 East Franklin, Street; 919/933-1324

【推荐2】Sending human travelers to Mars would require scientists and engineers to overcome a range of technological and safety obstacles. One of them is the enormous risk posed by particle radiation from the sun, distant stars and galaxies.

Answering two key questions would go a long way toward overcoming that: Would particle radiation pose too serious a threat to human life throughout a round trip to the red planet? And, could the very timing of a mission to Mars help protect astronauts from the radiation?

In a new article published in the journal Space Weather, an international team of space scientists with researchers from UCLA, answers those two questions.

That is, humans should be able to safely travel to and from Mars, provided that the spacecraft has adequate shielding (防护) and the round trip is shorter than approximately four years. And the timing of a human mission to Mars would indeed make a difference: The scientists determined that the best time for a flight to leave Earth would be when solar activity is at its peak, because the most dangerous and energetic particles from distant galaxies are deflected (偏移) during solar maximum.

Imaginably, the average flight to Mars takes about nine months, so it is reasonable that a human mission could reach the planet and return to Earth in less than two years,according to Yuri Shprits, a UCLA research geophysicist and co-author of the paper.:

“This study shows that although space radiation imposes (追使) strict limitations on how heavy the spacecraft can be and the time of launch, and it presents technological difficulties for human missions to Mars, such a mission is viable,” said Shprits, who also is head of space physics and space weather at GFZ Research Centre for Geosciences in Potsdam,Germany.