The Leaning Tower of Pisa was straight like a pole when the construction began in 1173. It started to shift direction soon after construction because of poor foundation in addition to the loose layer of subsoil(底土). At the beginning, it leaned to the southeast before the shaky foundation started to shift leaning towards the southwest. After the period of structural strengthening at the beginning of the 21^st century, now the Leaning Tower of Pisa leans at an angle of 3.97 degrees.

    In 1178, the shift in direction was observed for the first time when the construction had progressed further to the third floor. The tower was heavy for the three-meter foundation that was built on a weak area of land.

    For compensating(补偿) the leaning position, the builders started to construct the upper floors with one side higher than the other one. This caused the tower to lean in the other direction. This unusual structure led to the tower being actually curved. In spite of these efforts, the tower kept on leaning.

    The government of Italy started to plan prevention of the complete collapse of the tower in 1964. However, a request was put forward by the authorities to keep the leaning position because of the tourism industry of the region.

    After nearly two decades of careful planning by engineers, historians and mathematicians, the stabilization efforts for the Leaning Tower of Pisa started in 1990. The tower was closed for the general public and the people living nearby moved away. For reducing the total weight of the tower, its seven bells which represented the seven musical notes were removed. The tower was reopened for the general public on December 15, 2001.

    In May 2008, after removing another 70 metric tons of earth, the engineers announced that the tower had been finally stabilized and it would remain stable for at least 200 years.

    Mom and Dad are two of the most important people in your life.You probably see at least one of them every day. If your dad worships（崇拜）the Pittsburgh Stealers,you're likely to grow up being a big fan of that football team.And if your mom loves to read,you just might grow up carrying a book wherever you go,just like she does.

    Here are four ways you can stay.close:and build a strong relationship with your parents.

    ⑴Spent time together.How much time do you spend just enjoying each other's company?

    Instead of playing a computer game or watching TV,maybe you can ask your mom and dad to play with you.Go outside together,try a board game,or read a book out.

    ⑵Share your feelings and ask for help.Your mom or dad might not know that you're having a problem.Tell a parent if you're sad or struggling with something.

    ⑶Show your care. Some families are always kissing, hugging, and saying "I love you". It's important to show that you care for each other. In addition to kisses and hugs, kids and parents show their love by respecting each other, being caring, polite, and thoughtful.

    ⑷Whatever you do, do your best! You, don't have to be perfect, but when you do your best, you make your parents proud. It makes them happy to see how you're turning into such a great kid. Why? Because it lets them know they're doing a good job.

    The UK government has announced plans to tackle sources of air pollution, including popular wood-burning stoves, but its Clean Air Strategy, which was unveiled last week, fails to address the real problem.

    Although pollution from woodburning stoves is a relatively new problem for the UK, it has long been a major one in countries such as Canada and New Zealand. And the take-home message from them as to controlling the release of harmful particulates in the air is simple: ban wood burning.

    "There does not seem to be a limit below which there is no impact on health," says Gary Fuller at King's College London, whose team has shown that wood burning is now the source of a third of particulate pollution in UK cities.

    As New Scientist reported last year, families with wood burners are likely to be exposed to the highest levels of pollution and their neighbours are next in the firing line, given that the particulates produced can easily escape from homes. Despite this, the UK government isn't planning a ban. Instead, it wants "to prohibit the sale of the most polluting fuels", such as wet wood. What's more, lots of people with wood burners don't buy wood from shops. Instead, they scrounge it from wherever they can, with building waste one popular source. This is a disaster in pollution terms as treated or painted wood can release highly toxic chemicals when burned. The plan is also to "ensure that only the cleanest stoves are available for sale by 2022". But even the cleanest stove produces eight times as much pollution as a diesel truck, says Fuller.

    Some cities actually required old wood stoves to be replaced with cleaner new ones. That has helped, but wood burning remains a major source of pollution, says Fuller. In most cases, conventional gas central heating plus properly insulating (使隔热) your home is less harmful in global-warming terms than switching to a wood burner.

    Finally, there are separate but related EU laws that set limits on the maximum allowable concentrations of specific pollutants in the air at individual locations. The UK frequently breaches these: London's Oxford Street often hits its annual limit within the first weeks of each year. As a result, the UK government has lost a series of court cases brought by the environmental organization ClientEarth. Separately, on 17 May, the UK and five other countries were referred to the Court of Justice of the European Union for their repeated failures to keep to these limits. If the government really wants to clean up the UK's air, it has a lot more work to do.

    You may think there are no differences between British and American people. After all, they speak the same language, don't they? If you ask a British or an American person, he will probably tell you that there are differences. And the differences are quite great.

    What do British people think American people are like? The British think American people are very strange. They make a lot of noise and they laugh too loudly. They are rich, and they only think about money. But the British do say that American people are kind friendly people. They're happy to help you if you are in trouble.

    What do Americans think of the British? Well, they think the British are cold and very unfriendly. They are not interested in success or in making lots of money. They think British is the best country in the world. They look down on other countries. But Americans say that the British are quite hard workers. They are brave and honest. And in time of trouble they face difficulties happily.

    You can see that these ideas can cause misunderstanding between the British and Americans. But when American and British people become friends, they usually find things are not as bad as they expected.

    As technology develops, school students who are off class may have no fear of too much absence from class. A small robot may help those children recovering from a long-term illnesses in the hospital or at home. These children may feel isolated from their friends and classmates. The robot takes their place at school. Through the robot, the children can hear their teachers and friends. They also can take part in class from wherever they are recovering.

    Anyone who has had a long term illness knows that recovering at home can be lonely. This can be especially true of children. They may feel left out. Now these children may have a high-tech friend to feel less alone. And that friend is a robot. The robot is called AV1. AV1 goes to school for a child who is at home while recovering from a long-term illness. And the child's school friends must help. They carry the robot between classes and place the robot on the child's desk.

    A Norwegian company called No isolation created the robot. The co-founders of No Isolation are Karen Dolva and Marius Aabel. Dolva explains how the robot AV1 works. She says, from home, the child uses a tablet or phone to start the robot. Then they use the same device（设备）to control the robot's movements. At school, the robot becomes the eyes, ears and voice of the child. The child can take part in classroom activities from wherever she/he is recovering-whether at home or from a hospital bed. The robot is equipped with speakers, microphones and cameras make communicating easy.

    If you think you have two left feet but would love to be a good dancer then why not try your hand at dancing?

    That's exactly what I did five years ago and I immediately fell in love with dancing. To me, dancing is a magical experience: I've become fitter, look younger and feel more confident. I enjoy it so much that I will never give up this healthy pastime.

    It's very sociable as well. You meet people and make new friends while dancing the night away. Haven't you heard stories about how dancing inspired new romances or rekindled (重燃) old ones? My friends Joe and Rena just had their big day a few weeks ago after they met each other at a Ceroc workshop some three years before.

    The word “Ceroc” comes from the French language. Without the complicated footwork, it is easier to pick up by beginners. Another good thing about Ceroc is that while it is a partner dance, you don't have to bring a dancing partner.

    Other popular styles of dancing in the UK include ballroom, belly dancing, lindy hop, salsa, tango and tap dancing, just to name a few.

    No matter what types of dancing you do, one thing is for sure: you will become fitter. For office workers like me, dancing is good cardio exercise after a long day sitting in front of the computer screen. It also strengthens your muscles, improves your coordination(协调) and increases your physical confidence.

    Few people will end up being queens of the dance floor. The aim is not to win a competition but to enjoy the interaction(交流). As long as you do the right moves, keep the rhythm and most importantly keep an encouraging smile to your dancing partners, you will always be a winner!