阅读理解

    LONDON－Scientists have found an unusual way to prevent our planet from overheating: move it to a cooler spot. All you have to do is send a few comets (彗星) in the direction of Earth, and its orbit will be changed too. Our world will then be sent spinning into a safer, colder part of the solar system.

    This idea for improving our climate comes from a group of U. S. National Aeronautics and Space Administration (NASA) engineers and American astronomers. They say their plan could add another six billion years to the useful lifetime of our planet－effectively doubling its working life.

    The plan put forward by Dr. Laughlin, and his colleagues Don Korycansky and Fred Adams, needs carefully directing a comet or asteroid so that it passes close by our planet and sends some of its gravitational energy to Earth.

    “Earth's orbital speed would increase as a result and we would move to a higher orbit away from the Sun,” Laughlin said.

    Engineers would then direct their comet so that it passed close to Jupiter or Saturn. The comet would pick up energy from one of these giant planets. Later its orbit would bring it back to Earth, and the process would be repeated.

    In the short term, the plan provides an ideal way to global warming, although the team was actually concerned with a much greater danger. The Sun is certain to heat up in about a billion years and so “seriously compromise” our biosphere (生物圈) －by cooking us.

    That's why the group decided to try to save Earth.

    The plan has one or two worrying aspects, however. For a start, space engineers would have to be very careful about how they directed their asteroid or comet towards Earth. The smallest miscalculation (误算) in orbit could fire it straight at Earth--with deadly consequences.

    There is also the question of the Moon. As the current issue of Scientific American magazine points out, if Earth was pushed out of its current position, it is “most likely the Moon would be stripped away from Earth”. This would greatly change our planet's climate.

    Maybe it is true that we do not know what we have got until we lose it,but it is also true that we do not know what we have been missing until it arrives.

    It takes an hour to like someone,and a day to love someone,but it takes a lifetime to forget someone.Giving someone all your love is never an assurance that they will love you back.Do not expect love in return;but if it does not,be content it has grown in yours.Do not rely on one's appearance;it can trick you.Do not rely on wealth;even that fades away.Rely on someone who makes you smile,because it takes only a smile to make a dark day seem bright.

    There are moments in life when you miss someone so much that you just want to pick them from your dreams and hug them.Dream what you want to dream;go where you want to go;be what you want to be,because you have only one life and one chance to do all the things you want to do.

    The brightest future will always be based on a forgotten past.You cannot go on well in life until you let your past failures and heartaches go off.May you have enough happiness to make you sweet,enough trails to make you strong,enough sorrow to keep you human,enough hope to make you happy.The happiest of people do not necessarily have the best of everything;they just make the most of everything that comes along their way.Happiness waits for those who cry,those appreciate the importance of people who have touched their lives.Always put yourself in others' shoes.If you feel that it hurts you,it probably hurts the other person,too.

    When you were born,you were crying and everyone around you was smiling.Live your life so that when you die, you are the one who is smiling and everyone around you is crying.

    North America tours

    Tour North America and discover how the New World became the culturally diverse civilization it is today: the world's greatest melting pot is in your own backyard.

Boston: Colonial History

    Days: 4

    Get your walking shoes ready to follow the footsteps of the American Founding Fathers in Boston. Journey through the landmarks of the American Revolution in this historical city by walking down the Freedom Trail with a Colonial tour guide. Get out of the city with detours to Salem. Lexington, Concord and Plymouth, where you will see where the first shots of the American Revolution were fired.

Civil Rights in the South

    Days: 5

    Journey back to a time of revolution and brotherhood in the heart of the Civil Rights Movement. Follow the path of the marches through Atlanta, Montgomery and Birmingham, as well as the town of Selma, where a peace l protest erupted into what is now called" Bloody Sunday. "Pay respect to the key contributors to civil rights by visiting the Rosa Parks Museum and the home and church of the most famous civil rights activist of them all. Dr Martin Luther King, Jr.

    IL MUNC in Philadelphia

    Days: 4

    The Ivy League Model UN Conference (ILMUNC) is known as a unique educational experience for its focus on international affairs and networking. Students from across the continent will come together to debate and discuss pressing global issues as UN delegates. You can also explore some of downtown Philadelphia's finest attractions including the Philadelphia Museum of Art, the Liberty Bell. Independence Hall before or after the conference.

    Quebec City &Montreal Four Day Spring Tour

    Days: 4

    Montreal and Quebec City are two of the most diverse, beautiful and exciting travel destinations in Canada. Your tour through Quebec's Upper Town includes the beautifully lit National Assembly, Dufferin Terrace, and Chateau Frontenac. Walk along the 17^th-century cobblestone streets of Lower Town, then continue on to Montreal for a visit to Mont Royal, which boasts breathtaking views from the highest point in the cit.

    In Britain. Boxing Day is usually celebrated on December 26th, which is the following day after Christmas Day. However, strictly speaking, Boxing Day is the first weekday after Christmas. Like Christmas Day, Boxing Day is a public holiday. This means it's a non-working day in the whole of Britain. When Boxing Day falls on a Saturday or Sunday, the following Monday is the public holiday.

    The exact origin(起源)of the holiday is unclear. One of the thoughts is that during the Middle Ages, when great sailing ships were setting off to discover new land, a Christmas Box was placed by a priest(神父)on each ship. Those sailors who wanted to ensure a safe return would drop money into the box. It was sealed up and kept on board until the ship came home safely. Then the box was handed over to the priest in exchange for the saying of a mass of thanks for the success of the sailing. The priest wouldn't open it to share the contents with the poor until Christmas.

    One more thought is about the "Alms Box" placed in every church on Christmas Day. Worshippers(做礼拜的人) put gifts for the poor into it. These boxes were always opened the day after Christmas. That is why that day became known as Boxing Day.

    Today, many businesses, organizations and families try to keep the traditional spirit of Boxing Day alive by donating(捐赠) their time, services and money to aid Food Banks, providing gifts for the poor, or helping families in need. Besides, spending time with family and shopping are popular Boxing Day activities now.

 Imagine this. You need an image of a balloon for a work presentation and turn to an AI text- to- image generator, like Midjourney or DALL-E, to create a suitable image. You enter the prompt(提示词)" red balloon against a blue sky" but the generator returns an image of an egg instead.

What's going on? The generator you' re using may have been" poisoned". What does this mean?

Text- to- image generators work by being trained on large databasets that include millions or billions of images. Some of the generators have been trained by indiscriminately (任意地) scraping online images, many of which may be under copyright. This has led to many copyright infringement(侵害) cases where artists have accused big tech companies of stealing and profiting from their work.

 This is also where the idea of" poison" comes in. Researchers who want to empower individual artists have recently created a tool named" Nightshade" to fight back against unauthorised image scraping. The tool works by slightly changing an image's pixels(像素) in a way that confuses the computer vision system but leaves the image unchanged to a human's eyes. If an organization then scrapes one of these images to train a future AI model, its data pool becomes" poisoned". This can result in mistaken learning, which makes the generator return unintended results. As in our earlier example, a balloon might become an egg.

 The higher the number of" poisoned" images in the training data, the greater the impact. Because of how generative AI works, the damage from" poisoned" images also affects related prompt keywords. For example, if a" poisoned" image of a Picasso work is used in training data, prompt results for masterpieces from other artists can also be affected.

 Possibly, tools like Nightshade can be abused by some users to intentionally upload" poisoned" images in order to confuse AI generators. But the Nightshade's developer hopes the tool will make big tech companies more respectful of copyright. It does challenge a common belief among computer scientists that data found online can be used for any purpose they see fit.

 Human rights activists, for example, have been concerned for some time about the indiscriminate use of machine vision in wider society. This concern is particularly serious concerning facial recognition. There is a clear connect ion between facial recognition cases and data poisoning, as both relate to larger questions around technological governance. It may be better to see data poisoning as an innovative(创新的) solution to the denial of some fundamental human rights.