【推荐3】Losing a baby tooth can be fun for a kid. You can put it under your pillow and look forward to finding some money there in the morning. And then you can watch your new permanent(永恒的）tooth grow in its place.

But if a permanent tooth falls out, that's a problem. There isn't another one under the gum（齿龈）that can replace it. Unfortunately, this happens to some older people. And if permanent teeth fall out or need to be pulled, an older person might need dentures.

Dentures,known as false teeth, are a set of replacement teeth for any teeth that are missing.

There are partial dentures, which take the place of only a few teeth and prevent the others from changing position. If all the teeth are gone, the person would need complete dentures,which replace every tooth in the mouth.

Dentures can cause pains at first but take little time to get used to.They also need special care. They should be brushed daily with a special denture brush and cleanser and soaked(浸泡） in denture solution when not in the mouth.

Dentures are important for the old because, without teeth, it's hard to smile, talk, and eat properly. But it can be a little weird if you see someone take out his or her dentures. It can also be strange to see someone, like a grandparent, without dentures in because he or she won't have any teeth. Try not to make fun of the person because this could cause hurt feelings.

People usually lose their permanent teeth due to periodontal disease (牙周炎）， or gum disease, which is caused by bacteria that attack the gums. Diseased gums aren't strong and healthy, so teeth can get loose and fall out. Older people often have many cavities (洞） that have been filled over the years, and these fillings can weaken over time, leading to more tooth problems.

【推荐2】For incoming freshmen at western Connecticut's suburban Brookfield High School, lifting a backpack weighed down with textbooks is about to give way to tapping out notes and touching electronic pages on an iPad. A few hours away, every student at Burlington High School near Boston will also start the year with new school-issued ipads, each loaded with electronic textbooks and other online resources in place of traditional texts. Apple officials say they know of more than 600 districts that have launched what are called " one-to-one " programs.

At Burlington High in suburban Boston, Principal Patrick Larkin says the   $ 500 ipads is better than textbooks in the long term, though he said the school will still use traditional texts in some courses if suitable electronic programs aren' t yet available. Larkin said of textbooks, " but they' re pretty much outdated the minute they're printed and certainly by the time they're delivered".

But some experts warn that the districts need to ensure they can support the wireless infrastructure (设施 ), repairs and other costs that accompany a switch to such a tech-heavy approach. Mark Warschauer, an education and informatics(信息学)   professor said,   "I think people will like it.I really don't know anybody in high school that wouldn't want to get an iPad," he said. "We' re always using technology at home,   then when you' re at school it' s textbooks. So it' s a good way to put all of that together. " Districts are varied in their policies on how they police students'   use.

And the nation' s textbook publishing industry, accounting for $ 5.5 billion in yearly sales to secondary schools, is taking notice of the trend with its own shift in a competitive race toward developing curriculum specifically for ipads.Jay Dickey, executive director of the Association of American Publishers' schools division, said all of the major textbook publishers are moving toward electronic offerings, but at least in the short term, traditional bound textbooks are here to stay. "I think one of the real key questions that will be answered over the next several years is what sort of things work best in print for students and what sort of things work best digitally. "

【推荐3】If you live in southwest Virginia, don’t be surprised at the sight of a drone(无人机) winging its way, doing airborne delivery over your neighborhood.

On October 20,2019,wing,an American multinational company, began the most advanced trials of commercial drone delivery in Virginia. Residents can now use a smartphone app to order items from Wing partners such as Sugar Magnolia. A Wing drone never sets down at destinations, instead gently lowering the package with a rope outside the customer's door.

Though Wing is the first American company to receive Federal Aviation Administration(FAA)approval to use commercial drones as a widespread service. it is not the only one. On October 22,2019,multinational delivery company UPS, which had also received FAA approval for its drone fleet, announced it would soon begin trial deliveries of goods from health care company CVS. Meanwhile, ridesharing company, Uber, which had partnered with McDonald's, hoped to use its drones to deliver food to hungry customers in San Diego, CA, before the end of 2019. Amazon also plans on testing its trial deliveries of goods in a yet-to-be-determined location in the upcoming months.

Every company's drones can carry packages weighing up to five pounds, and the series of trial are hortative, but widespread drone delivery still has many challenges. These include basic issues like finding places for drones to land, reducing noise pollution, and even ensuring the drones don't run into each other while airborne.

To help sped up the process, NASA announced the Urban Air Mobility Grand Challenge. The competition challenges airspace service providers to find creative solutions to the issues, so that drone deliveries can become a reality soon. “We are moving fast,” said NASA Administrator Jim Bridenstine. “We want to see by 2028 at least one city--maybe more than one--have the ability to control hundreds of drone delivery systems. They could be carrying goods, doing thousands of missions every day.”

【推荐1】In 2015, researchers from Australia's Deakin University published one of the first studies measuring food's physical effect on the left hippocampus(海马体), a seahorse-shaped brain region crucial for memory, learning and decision making. It is also one of the first areas to shrink in people with dementia(痴呆). 252 people filled out diet surveys and then underwent scans that measured their brains. Four years later, they returned for another scan.

The study found that the left hippocampus was heftier in the healthy eaters than in the unhealthy ones, regardless of age, sex, weight, exercise habits or general health. The average difference was 203 square millimeters, nearly one third of a square inch. Sounds small, but that's room for a lot of extra brain cells. And strong new evidence showed that eating the right food and skipping the wrong stuff could help protect against declines in thinking and memory that lead to dementia.

"Plant-based diets may protect against memory decline and dementia," says lead researcher Claire McEvoy, RD. How is the power food working with your brain cells? Animal and test-tube experiments suggest that vitamins and fatty acids found in the plant food help new cells make copies of DNA when they divide and multiply. Meanwhile, the high-fat and the high-sugar processed food harms brain cells by leaving brain tissue damaged by free radicals (自由基). This may hold back brain plasticity, making the processed food an especially big threat for the developing brains of kids.

While food emerges as an important brain protector, experts say brain supplements (补充剂)aren't all that effective. These pills and capsules may contain many ingredients. But actually, studies show that they do not activate brain cells in a significantly positive way. "Let the buyer be aware of it," says David Hogan, MD, a specialist at Calgary University.

【推荐3】Cheerleading is the fastest growing women’s sport, yet many Americans think it can’t satisfy the standards and qualifications of a sport. In addition, they fail to distinguish between sideline cheerleaders and competitive ones. Sideline cheerleaders’ main goal is to entertain the crowd and lead them with team cheers, which should not be considered a sport. However, it is true of competitive cheerleading.

Competitive cheerleading includes lots of physical activity. Cheerleaders must learn to fall and perform many complex actions, like lifts and tosses. This is where the “fliers” are thrown in the air, held by “bases” in different positions that require strength and cooperation with other teammates. The whole routine has to be completed in less than three minutes and 15 seconds and the cheerleaders are required to stay within a certain area. Just like gymnasts, they are awarded points for difficulty, technique, creativity and sharpness. Cheerleading is a team sport, so without cooperation, first place is out of reach.

Cheerleading is the major cause of serious sports injuries to women due to the fact that cheerleaders always perform without any equipment to protect them. While many athletes in other sports are well protected, smiling cheerleaders are tossed into the air and fall down into the arms of trusted teammates. The fliers must remain tight all the time so that their bases can catch them safely. Because cheerleading is not recognized as a sport by many schools, proper equipment isn’t provided to ensure safety. Therefore, more recognition of competitive cheerleading as a sport would decrease the number of injuries.

Competitive cheerleading is a physical activity governed by rules under which a winner can be declared and its primary purpose is to compare the skills of participants. Hopefully, cheerleading will become as well-known a sport as football and basketball, and even appear in the Olympics since cheerleaders are just as athletic and physically fit as those involved in the more accepted sports.

【推荐1】Sun Xun: Time Spy

Chinese artist Sun Xun uses woodblock (木板) printing, a centuries old method to change the 215 century medium of film. In Time Spy, Sun Xun has created a 3D world that walks freely across time and cultures that draws its inspiration from both Eastern and Western art, history, myth (神话), especially imagination.

To produce Time Spy, the artist and his team cut more than 10,000 woodblocks to make beautiful patterns, and then looked at every part carefully to create the cartoon. The choices of the woodblocks that were used to create the film will be shown publicly in the exhibition.

Opened: Tuesday-Sunday: 10 am-5 pm   Friday: 10 am-9 pm

Closed: Monday

Final admission to the exhibition is one hour before it closes. Due to high demand,especially on Fridays, Saturdays and Sundays, we strongly suggest you buy or book your ticket in advance.

A ticket is required for admission to the exhibition. All tickets are marked for a detailed date and time.

Adults: $20; Seniors and Students: $18; Children (6-12): $8; Children (5 and under): Free Tickets required: limited to six tickets per reservation. Discounted ticket rates are available for groups of 10 or more. Tickets must be bought at least four weeks in advance to get your discount.

【推荐2】Give your dead batteries (电池) a new life. Recycle them!

Batteries are used to power clocks, computers, tools and more. However, your batteries have some serious power when their lives are over.

WHY TO RECYCLE BATTERIES:

Remember, batteries are harmful waste. This means we should properly throw them away. You may not think one little battery can cause that much pollution. But don’t think of it as just one battery—there can be millions. In Canada, each person uses about 20 single-use batteries every year. That’s about 700 million batteries! If all these batteries end up in landfills (垃圾填埋场), the heavy metals inside them can get into the water, land and air. It can be harmful to humans and wildlife.

By recycling single-use batteries instead of throwing them away, you can cut down pollution and also help save energy. All batteries are mainly made of plastic and valuable metals. Through recycling programs, dead batteries can be changed into something useful like steel products, or even new batteries.

HOW TO RECYCLE BETTARIES:

Make a difference by starting to collect batteries at your home or school today. You can prepare a box for battery collection and invite friends, family and classmates to bring in old batteries to be recycled.

There are many ways to deal with your batteries. You can:

● Find a Call to Recycle public collection station near you.

● Ask the store where you bought the batteries if you can return them there.

● Communicate with your local city government to find out if there are special programs for recycling used batteries!

For more information, visit https://ecokids.ca/batteries.

【推荐3】My friend, Monty Roberts owns a horse ranch (养马场). The last time I was there he introduced me a story like this: There was a young man who was the son of a horse trainer, who would go from stable (马厩) to stable, race track to race track, farm to farm and ranch to ranch, training horses. So the boy's school career was continually interrupted. When he was a senior, he was asked to write a paper about what he wanted to be and do when he grew up.

That night he wrote a seven-page paper describing his goal of someday owning a horse ranch. He wrote about his dream in great detail and he even drew a diagram of a 200-acre ranch, showing the location of all the buildings, the stables and the track. He also drew a detailed floor plan for a 4,000-square-foot house that would sit on a 200-acre dream ranch. He put a great deal of his heart into the project and the next day he handed it in to his teacher. Two days later he received his paper back. On the front page was a large red F with a note that read, “See me after class.”

The boy with the dream went to see the teacher after class and asked why he received an F. The teacher said, "This is an unrealistic dream for a young boy like you. You have no money. You have no resources. Owning a horse ranch requires a lot of money. You have to buy the land. There's no way you could ever do it... If you will rewrite this paper with a more realistic goal, I will reconsider your grade.”

The boy went home and thought about it long and haul. He asked his father what he should do. His father said, "Look, son, you have to make up your own mind on this. However, I think it is a very important decision for you.” Finally, after a week, the boy turned in the same paper, making no changes at all. He stated, “You can keep the F and I'll keep my dream."

Monty then turned to me and said, "I tell you this story because you are sitting in my 4, 000-square-foot house in the middle of my 200-acre horse ranch. I still have that school paper framed over the fireplace.” He added, "The best part of the story is that two years ago that same schoolteacher brought 30 kids to camp out on my ranch for a week. When the teacher was leaving, he said, “Look, Monty, when I was your teacher, I was something of a dream stealer. During those years I stole a lot of kids’ dreams. Fortunately you had enough ambition not to give up on yours.”