Houses fall down. Trees fall over. Large holes form in the ground. Could Alaska be sinking? That's what some villagers in Alaska have been asking themselves recently and scientists think they know why. Warmer temperatures may be causing Alaska's frozen ground to thaw (解冻).

    About 85 percent of Alaska's land surface has permafrost (永久冻结带). Permafrost supports the ground above it—including trees, houses, and roads. But why is the permafrost thawing?

    Some scientists say that human-caused pollution is leading to global warming. And most scientists agree that Alaska has been getting warmer. They say that the warmer temperature is causing permafrost to thaw in some areas. The thawing permafrost can cause problems for people, plants, and animals.

    The collapsing (倒塌) is a problem in the villages in Alaska which are built on permafrost, and some of them may have to move to safer ground, where there is no permafrost.

    The Alaskan town of Glennallen saw its old post office collapse. And, according to James Walters, a permafrost expert at the University of Northern Iowa, house-moving companies have been very busy.

    “Melting permafrost can also destroy trees and forests,” Walters said. “When holes in the ground form, trees fall into them and die. This could turn a forest into a swamp (沼泽), and animals which need the forests will have to move elsewhere.”

    “The melting could cause severe problems.” Walters says, “This could take hundreds of years, but in the end Alaska will look quite different from what it looks like now.”

    The deadliest Ebola outbreak in history that has so far killed almost 1000 people in Guinea, Liberia, Sierra Leone and Nigeria in West Africa has caused fear around the world.

    The outbreak is unprecedented（空前的）both in infection numbers and in geographic scope. Officials from the World Health Organization (WHO) said earlier this month the outbreak “is moving faster than our efforts to control it”, reported CNN. So far, the battle against the virus doesn't appear to be slowing down.

    The Ebola virus is terrifying no matter where it strikes: It's a disease with no cure that causes headaches and fever, severe diarrhea(腹泻), vomiting and bleeding and has been known to kill up to 90 percent of its victims.

    It is understandable for people to be panicked, but those living outside Africa shouldn't be particularly concerned about contracting the virus, says a Washington Post article.

    This is because transmission of Ebola requires direct contact with an infected person's blood, vomit or other bodily fluids during the period that he or she is contagious(接触传染的). It is something that is extremely unlikely for anyone but healthcare workers. The virus is not spread by coughing or sneezing.

    Media outlets in the US and the UK are using terrifying headlines, wrongly claiming that people infected with the virus have traveled to their countries.

    James Ball at The Guardian says the Ebola outbreak in Africa is tragic, but it is important to keep a sense of proportion. Other infectious diseases, including common influenza, are far, far deadlier.

    Dear friend, do you know the boy in the picture? He is Wang Yuan, a member of the Chinese boy band, TFBOYS. Do you want to know more about him? Follow me, please.

    Wang Yuan was born on November 8^th , 2000 in Chongqing. His English name is Ray, he is senior high school student now, he is good at singing, dancing and playing the piano. He can also write song alone. He and another two boys formed the boy band TFBOYS in 2013. They are very popular with the young girls and boys in China now.

    On February 10^th,2017,Wang Yuan made a short speech on good quality education(优质教育）in English at the United Nations in front of 500 people from around the world. It's great. As for middle school students, we should learn from Wang Yuan, and put our hearts into what we are doing to make a difference in our daily lives.

    Are you looking for some new and exciting places to take your kids to? Try some of these places:

    Visit art museums. They offer a variety of activities to excite your kids' interest. Many offer workshops for making hand-made pieces, traveling exhibits, book signings(签名) by children's favorite writers, and even musical performances and other arts.

    Head to a natural history museum. This is where kids can discover the past from Dinosaur (恐龙) models to rock collections and pictures of stars in the sky. Also, ask what kind of workshops and educational programs are prepared for kids and any special events that are coming up.

    Go to a Youtheater. Look for one in your area offering plays for child and family visitors. Pre-show play shops are conducted by area artists and educators where kids can discover the secret about performing arts. Puppet (木偶) making and stage make-up are just a couple of the special offerings you might find.

    Try hands-on science. Visit one of the many hands-on science museums around the country. These science play-lands are great fun for kids and grown-ups alike. They'll keep your child mentally and physically active the whole day through while pushing buttons, experimenting, and building. When everyone is tired, enjoy a fun family science show, commonly found in these museums.

    The Secretary-General of the U.N. has always been chosen in private meetings. But for the first time in its 70-year history, part of the selection process is taking place in public.

    At least eight countries have announced their candidates (候选人) for the position, among whom are women, including Irina Bukova from Bulgaria, Susana Malcorra from Argentina and Helen Clark from New Zealand. 56 countries says the next U.N. chief should be a woman. There have been eight U.N. chiefs, none of whom was a woman.

    All member states were permitted to ask the candidates questions during two hour-long meetings last week in the U.N. General Assembly (联合国大会). The candidates were also asked some of the 1,000 questions written by people on social media.

    They were asked questions about development, how they would improve efforts to create peace and how they would protect human rights.

    The U.N. Security Council will examine the candidates' backgrounds. Then the 15 members will vote secretly until one person is chosen. The General Assembly will then vote on whether to accept the choice.

    Britain, China, France, Russia and the United States are the five permanent members of the Security Council. Experts say they are likely to have more influence on who will be the new secretary-general than the 10 non-permanent nations on the council.

    The Security Council will begin to discuss who will be named the next secretary-general in July. A new secretary-general may not be confirmed until as late as November.

    The U.N. has a tradition of choosing its new leader from a part of the world different from its current leader. U.N. Secretary-General Ban Ki-moon is from Asia. The previous U.N. chief was Kofi Annan, who was from Africa.

    Dan Thomas is a spokesman for the president of the General Assembly. He says there is no rule that says where a new secretary-general must come from. But most observers say the new U.N. chief will not be from Asia or Africa.

    Your house may have an effect on your figure. Experts say the way you design your home could play a role in whether you pack on the pounds or keep them off. You can make your environment work for you instead of against you. Here are some ways to turn your home into part of your diet plan.

    Open the curtains and turn up the lights. Dark environments are more likely to encourage overeating, for people are often less self­conscious (难为情) when they're in poorly lit places—and so more likely to eat lots of food. If your home doesn't have enough window light, get more lamps and flood the place with brightness.

    Mind the colors. Research suggests warm colors fuel our appetites. In one study, people who ate meals in a blue room consumed 33 percent less than those in a yellow or red room. Warm colors like yellow make food appear more appetizing, while cold colors make us feel less hungry. So when it's time to repaint, go blue.

    Don't forget the clock—or the radio. People who eat slowly tend to consume about 70 fewer calories (卡路里) per meal than those who rush through their meals. Begin keeping track of the time, and try to make dinner last at least 30 minutes. And while you're at it, actually sit down to eat. If you need some help slowing down, turn on relaxing music. It makes you less likely to rush through a meal.

    Downsize the dishes. Big serving bowls and plates can easily make us fat. We eat about 22 percent more when using a 12­inch plate instead of a 10­inch plate. When we choose a large spoon over a smaller one, total intake (摄入) jumps by 14 percent. And we'll pour about 30 percent more liquid into a short, wide glass than a tall, skinny glass.