阅读理解。

    One form of social prejudice against older people is the belief that they cannot understand or use modern technology. Activities like playing computer games, going on the Net and downloading MP3s are only for the youngsters. Isn't it unfair that older people enjoying a computer game should be frowned(皱眉) upon by their children and grandchildren?

    Nowadays older people have more control over their lives and they play a full part in society. Moreover, better health care has left more people in their sixties and seventies feeling fit and active after retirement. Mental activity, as well as physical exercise, can contribute to better health. Playing computer games is a very effective way of exercising the brain.

    When personal computers were first introduced, most older people didn't believe they would ever familiarize themselves with it. Now computers have been around for a few generations and retired people have gradually become more relaxed about using them for fun. Gamers over 65 prefer playing puzzle games and card games. Kate Stevens, aged 72, says: “I find it very relaxing. It's not very demanding, but you still need to concentrate.”

    Another development that has favored “grey games” is a change in the type of videogames available on the market. There's a greater variety of games to choose from, including more intellectual and complex strategy(策略) and simulation(模拟) games. Internet Chess and Train Simulator are among the most popular of these. Train Simulator is based on real-world rail activities. Players can choose from a variety of challenges, such as keeping to a strict-timetable and using helper engines during a winter storm.

    Some people argue that “grey gamers” simply don't have the skills required for computer games, and that teenagers are better. This couldn't be further from the truth. Most computer games require the kind of analytical thinking that improves with practice, which means that the “grey gamers” may well be far better than gamers half a century younger than them. In games where speed is the main consideration, older people would be at a disadvantage because they may have slower reaction times. On the other hand, “grey gamers” have a preference for slower paced, mind challenging games.

    We've considered several ways of paying to cut in line: hiring line standers, buying tickets from scalpers (票贩子), or purchasing line-cutting privileges directly from, say, an airline or an amusement park. Each of these deals replaces the morals of the queue (waiting your turn) with the morals of the market (paying a price for faster service).

    Markets and queues—paying and waiting—are two different ways of allocating things, and each is appropriate to different activities. The morals of the queue, “First come, first served, have an egalitarian (平等主义的) appeal. They tell us to ignore privilege, power, and deep pockets.

    The principle seems right on playgrounds and at bus stops. But the morals of the queue do not govern all occasions. If I put my house up for sale, I have no duty to accept the first offer that comes along, simply because it's the first. Selling my house and waiting for a bus are different activities, properly governed by different standards.

    Sometimes standards change, and it is unclear which principle should apply. Think of the recorded message you hear, played over and over, as you wait on hold when calling your bank: “Your call will be answered in the order in which it was received.” This is essential for the morals of the queue. It's as if the company is trying to ease our impatience with fairness.

    But don't take the recorded message too seriously. Today, some people's calls are answered faster than others. Call center technology enables companies to “score” incoming calls and to give faster service to those that come from rich places. You might call this telephonic queue jumping.

    Of course, markets and queues are not the only ways of allocating things. Some goods we distribute by merit, others by need, still others by chance. However, the tendency of markets to replace queues, and other non-market ways of allocating goods is so common in modern life that we scarcely notice it anymore. It is striking that most of the paid queue-jumping schemes we've considered—at airports and amusement parks, in call centers, doctors' offices, and national parks—are recent developments, scarcely imaginable three decades ago. The disappearance of the queues in these places may seem an unusual concern, but these are not the only places that markets have entered.

Summer Programs for Teens

    University of Maryland: TERP Young Scholars

    This program is the perfect summer camp for academically talented teenagers who want to pursue academic interests, explore career opportunities, and discover college life at the University of Maryland.

    During three weeks of intellectual exploration, teens can study with students who share similar interests, and communicate with some of the university's best teachers. Upon successful completion, students can earn three college credits.

    Carpe Diem: The University-bound Adventure

    Carpe Diem supports both American and international students in applying to a university by providing private consultation. This 2-week experience also includes tours of famous East Const universities Students will also have the opportunity to build their resumes (简历) by working with writing experts.

    Great Books Summer Program

    This is a lively, warm and welcoming summer camp community of outstanding teens, who love literature and ideas In the past eleven years, it has gathered middle and high school students from across the world to read selections from the greatest works of literature, experience heated discussions and enjoy summer camp fun with other literary-minded students. Participants can gain confidence in their ability to read a text closely and express their ideas clearly both verbally and in writing.

    Zeal Travel

    We offer our teens two week and three- week long trips to Hawaii, Alaska, Australia and Spain. All trips include 15-25 hours of community service activities.

    Depending on your trip of choice, you'll be helping Hawaiians protect their forest ecosystem, caring for dogs in Spain, working with Habitat for Humanity, and much more. Every trip also includes exciting outdoor activities like surfing, driving, ice-climbing, hiking and more. The possibilities are endless and there is a zeal trip for every interest.

    Florence, Italy

    Who should go: art lovers, Renaissance historians and leather handbag shoppers with high credit limits.

    When to go: spring or fall. Travelers usually avoid summer in Florence.

    Paris, France

    Who should go: starving artists, Henry Miller fans, traditional food lovers.

    When to go: spring is the best time. That's what they all say, anyway. Autumn isn't bad, either, but I'd rather be rooting around the south of France in search of truffles (松露) in autumn. Summer in Paris isn't bad, really.

    Amsterdam, Holland

    Who should go: lovers of Dutch Master (artists I mean, like Rembrandt, not cigars), bicyclists—it's a bike city in a flat land.

    When to go: it can rain at any time in Amsterdam, but that's not a reason for not visiting this fascinating city. Off season tourists will be rewarded with good enough weather to stick around. Summer is good for sun lovers.

    Madrid, Spain

    Who should go: night owls—Madrid never sleeps, art lovers—the Prado is second only to the Louvre in presenting serious art, party-goers.

    When to go: spring, when days are warm and the nights are pleasantly cool. Demand for outside eating and drinking starts becoming stronger in March or April. Street life peaks in June and then slows in July and August as the temperature peaks. Autumn is also good, although you'll risk some rains.

    Venice, Italy

    Who should go: romantic dreamers who like walking through automobile-free streets, your mother (she'll want you to take her there, trust me), almost anyone who wants to see something really different and romantic.

    When to go: February is the time when the famous Venice Carnival is held and the weather is usually cold and foggy—perfect weather for Venice. Summer? A large number of tourists in shorts and whiny children ruin the atmosphere. You'll greatly enjoy yourself there in spring and early fall.

A 293-million-mile journey of the NASA Perseverance rover (探测器) to Mars: ended successfully on February 18, 2021, with a picture-perfect landing inside the Jezero Crater. The car-sized, six-wheeled rover, nicknamed Percy is the US space agency's biggest and most advanced explorer to date. Its primary mission is to search for signs of ancient microbial (微生物的) life on Mars.

Landing on Mars is extremely tricky. The Red Planet's gravitational pull causes approaching spacecraft to go faster to high speeds, while its thin atmosphere-just 1 percent that of Earth's-does little to help slow it down as it approaches the surface.

The scientists had to reduce Percy's 12,000 mph speed to a safe landing speed of less than five mph-in just six and a half minutes. The target entry angle also had to be a precise 12 degrees-any steeper, and the spacecraft would burn up; any flatter, and it would get lost in space. It is no wonder that the final approach is often referred to as the "seven minutes of terror. "

Upon attaining a manageable speed, Percy briefly flew over the Martian surface to seek out the perfect landing spot. Its complex map-reading system rapidly scanned the area and matched it with maps in its database to find the best location.

The NASA scientists will spend the next two months testing Percy's scientific instruments. Once ready, the rover will begin to carry out its mission.

"Perseverance is the smartest robot ever made, but confirming that microbial life once existed carries an unusually large burden of proof," said Lori Glaze, director of NASA's Planetary Science Division. "While we'll learn a lot with the great instruments we have aboard the rover, it may very well require the far more well-equipped laboratories and delicate instruments back here on Earth to tell us whether our samples (样本) carry evidence that Mars once harbored life. "