1 . Named “America’s Finest City” due to its hospitality, beauty and ideal climate, San Diego is located on the border with Mexico. The residents are so active outdoors that it is called “Sportstown, the U.S.A.”. San Diego’s 70 miles of beaches are a heaven for swimmers, surfers, divers, boaters and sunbathers. Another favourite outside activity is golf. With 100 courses (about 50 of them public), San Diego is a golfers’ paradise. Many San Diego residents came here first as tourists, who were attracted by San Diego’s sunny beaches, nearby mountains and deserts, plus the cultural delights of any big city. The world-famous San Diego Zoo, SeaWorld Adventure Park, Wild Animal Park, museums and other attractions attract visitors from around the world.

The zoo is home to some 4,000 animals, including the world’s largest group of parrots. Animals are displayed in natural settings, and there is a petting zoo for children. By contrast, the Wild Animal Park is a wildlife preserve with an area of over 2,000 acres and more than 3,000 free-roaming (自由漫步的) animals in natural habitats.

In addition to housing the zoo, Balboa Park is home to several museums and attractions, including an aerospace museum, an art and history museum, the Old Globe Theatre, science museums and even a railroad museum. Free concerts are offered frequently. Another popular attraction is the SeaWorld, a 190-acre marine park.

San Diego’s varied attractions, as well as its business climate, offer many opportunities for students to explore the local culture, meet people from around the world, and gain business experience. At San Diego State University, for example, students in the American Language Institute’s study tour program learn English both in the classroom and while sightseeing.

3 . “You need to sign this,” my son Joe informed me. “What is it?” I asked. Rolling his eyes with a sense of impatience, Joe replied, “Your permission. And it’s due tomorrow!”

I learned that Joe’s sixth-grade class would be taking a field trip to the state capital. “That sounds like fun,” I said. “I’ve always wanted to go there.” “You can’t come!” Joe answered. Puzzled, I asked. “Why not?” “Because you always come on field trips!”

Of course, I always joined his class on field trips. Being a chaperone (监护人) on a field trip is one of the advantages that comes with being a mom, a vacation day in a career that offers few opportunities for a change of scenery. “You don’t want me to be a chaperone?” “Give someone else’s mom a chance,” he suggested. What was surprising was how much I minded being so impolitely removed from the short list of willing chaperones by my own son.

When Joe was in kindergarten, his class planned a pretend trip to Norway. The day before the trip, Joe woke up not feeling well.

After learning that he didn’t have a fever, I asked, “You don’t want to miss getting ready for the trip to Norway, do you?” “I guess not,” he said.

But when I picked him up at the end of the day, the teacher whispered, “Joe got a little upset today.” “What happened?” “He doesn’t want to go to Norway without you.” So that was what had been bothering my 5-year-old. He thought his class was really flying to Norway on their wooden chairs in their paper airplane. He believed those passports and tickets he and his classmates had been making were the real deal.

Preadolescence fell upon my family as my husband and I found ourselves preparing for our son’s upcoming teen years with the same trepidation as someone about to climb an ice-covered mountain wearing high heels.

Joe needed to take a field trip without me accompanying him. And I needed to let him. I’m glad he doesn’t need me all the time.

4 . Exercise helps to keep us in good health. Doctors at the American Heart Association suggest getting at least 150 minutes of proper physical activity every week. Many people exercise for a few minutes every day or every other day. So, getting 150 minutes every week is easy.

But what about those times when you are sick? If you do not feel well, should you keep following your exercise habit? Following are the answers from health experts.

Edward R. Laskowski is a doctor at the Mayo Clinic. He and other experts have a general rule about exercising when you are sick. It is usually fine to exercise properly (not hard), he explains, if your symptoms are all “above the neck”. These signs may include a runny nose, sneezing (打喷嚏) or a sore throat.

Geralyn Coopersmith, a physical fitness trainer who has written several books on exercise offers similar advice. However, both Coopersmith and Dr. Laskowski suggest taking a break from exercising if signs of your illness appears “below the neck”. Pay special attention to symptoms such as chest congestion (胸闷), bad cough or pain in the stomach.

There are other symptoms that can tell you to avoid exercise. They include a higher than normal body temperature, a sense of feeling very tired, and widespread muscle pain.

Both Coopersmith and Dr. Laskowski suggest listening to your body. If you feel really bad, take a break and let your body rest. If you don’t feel too bad, these experts both suggest cutting down the amount of exercise. For example, if you usually run, take a quick walk instead.

5 . Sports play a key role in the physical and mental development of children. While it’s great to see a child succeed in one sport. it’s important to keep their activities in balance. Participation in multiple sports enables children to build a solid foundation of movement skills. Aside from this, here are some other good reasons why kids should be encouraged to play multi-sports.

Repetitive (重复乏味的) movements can overstress growing bodies which later on can lead to injuries. With multi-sports, each sport works the body slightly differently. This will lead to fewer overuse injuries.

Also, kids who overspecialize in one sport may end up losing interest and eventually quit. Specializing in a sport raises expectations and may put too much pressure on young kids. Having a variety of experiences will keep children interested and motivated, and even make them enjoy sports without any pressure.

Multi-sports also allow kids to experience different roles. Being a goalkeeper in a football team is very different from being a point guard in basketball. Being exposed to baseball develops better hand-eye coordination (手眼协调). Soccer develops better footwork. Volleyball develops jumping and hand-eye coordination. Martial arts develop strength, mobility, and discipline (自制力). Swimming develops full-body coordination and strength. The list goes on and on! Participation in multiple sports broadens a child’s developmental, social, and situation al experience. It opens opportunities to become a better competitor and a promising athlete—flexible and energetic.

Many sports superstars like Stephen Curry achieved their standing today by playing multiple sports. Curry played basketball, but he also played baseball, football, soccer and everything else in a sports buffet. What worked for Curry, experts say, could work for most of us.

Aside from developing a wide range of sports skills, more importantly, multi-sports provide opportunities for children to discover their liking. With the help of the right coaches, sports become fun. inspiring kids’ interests. So if you can’t decide whether your child should focus on one sport or try some different sports. I hope you can make a better decision now.

6 . Walking over water might sound like something unbelievable. In fact, people do it all the time. How? Almost all of the world’s liquid fresh water lies underground. This stash beneath our feet is called groundwater.

Earth is a water planet, but most of its H20 is in the oceans. Only about 2.5 percent of the planet’s water is fresh water. Of that, nearly 69 percent is frozen in glaciers (冰川) and ice caps. And about 30 percent is ground-water—much more than the 1.2 percent that flows through rivers and fills lakes.

Groundwater is found almost everywhere on Earth. It hides under mountains, plains, and even deserts. Tiny gaps between rocks and soil grains take in and hold this water like a sponge. forming buried bodies of water called aquifers (地下蓄水层). Together, they hold about 60 times as much water as the world’s lakes and rivers combined. Groundwater is a key part of the earth’s water cycle. Rain and melted snow go down into the ground. The water can stay there for thousands of years. Some groundwater naturally runs out onto the earth’s surface through springs. It also flows into lakes, rivers, and wetlands. People get groundwater through wells for drinking, watering crops, and other uses. People draw more than 200 times as much groundwater from the earth as oil every year.

As human-caused climate change dries out parts of the planet, demand for groundwater may rise. At the same time, climate change may intensify (加剧) storms. Heavier rain is more likely to rush straight into streams and storm drains, instead of going into the soil. So, there may be less groundwater around.

Many of the world’s aquifers already seem to be drying up. Twenty-one of the earth’s 37 biggest aquifers are becoming smaller, satellite data show. The most dried-out aquifers are near big cities, farms, or dry regions. As groundwater stores dwindle, they hold less water to refill rivers and streams, thus threatening freshwater ecosystems. In California, drying up the ground may even be causing small earthquakes.

7 . While teenagers who are at risk of depression with risky behaviors — drinking alcohol, smoking cigarettes and cutting classes often alert parents and teachers that serious problems are brewing, a new study finds that there’s another group of adolescents who are in nearly as much danger of experiencing the same mental symptoms.

These teens use tons of media, get insufficient sleep and have a sedentary (不爱活动的) lifestyle. Of course, that may sound like a description of every teenager on the planet. But the study wars that it is teenagers who engage in all three of these practices in the extreme that are truly in a dangerous position. Because their behaviors are not usually seen as a red flag, these young people have been called the “invisible risk” group by the study’s authors.

The study’s authors surveyed 15,395 students and analyzed nine risk behaviors, including excessive alcohol use, illegal drug use, heavy smoking and high media use. Their aim was to determine the relationship between these risk behaviors and mental health issues in teenagers. The group that scored high on all nine of the risk behaviors was most likely to show symptoms of depression; in all, nearly 15% of this group reported being depressed, compared with just 4% of the low-risk group. But the invisible group wasn’t far behind the high-risk set, with more than 13% of them exhibiting depression.

The findings caught Carli off guard. “We didn’t expect that,” he says. “The high-risk group and low-risk group are obvious, but this third group was not only unexpected. It was so distinct and so larger — nearly one third of our sample — that it became a key finding of the study.”

Carli says that one of the most significant things about his study is that it provides new early warning signs for parents, teachers and mental health-care providers. And early identifications, support and treatment for mental health issues, he says, are the best ways to keep them from turning into full-blown disorders.

9 . Online jobs have opened the door for many people to earn a living (谋生) or make some extra money from the comfort of their homes. This includes teens as well. If you’re looking for such a job, here are some choices you can consider.

Customer Service

If you are 16 years old and over, you have a chance to work with Uhaul as a customer service person. You just need to have a good pair of head-phones and high-speed Internet in order to do this job. Basic pay starts at $7.50an hour.

Sell Items Online

Selling items online is one of the easiest ways to make quick cash. Teens can turn it into a good business by selling things on Bonanza. You need to start sorting through (分类) items at your home that are no longer being used and list them for sale.

Take Surveys

Another easy task teens can do to earn money is to take surveys online. You don’t need any work experience to do this and can be as young as 13 years old to get started. Survey sites like VIP Voices, Swagbucks, Harris Poll, E-Poll, and Paid Viewpoint allow teens to start taking surveys for cash and gift cards. And your opinions should be expressed clearly in English.

Etsy

Do you love to make new things? You can open up an Etsy shop to share your works. Etsy is great for DIYers who can create new products. If you are under 18, you just need a parent who is willing to help manage your shop.

10 . Scientists say they have developed a system that uses machine learning to predict when and where lightning will strike. Researchers report the system is able to predict lightning strikes up to 30 minutes before they happen within a 30-kilometer area. Lightning is a strong burst of electricity in the atmosphere. Since it carries an extremely powerful electrical charge, it can cause very deadly results. European researchers have estimated that between 6,000 and 24,000 people are killed by lightning worldwide each year. For this reason, climate scientists have long sought to develop methods to predict lightning.

The system tested in the experiments uses a combination of data from weather stations and machine learning methods. The researchers developed a prediction model that was trained to recognize weather conditions that were likely to cause lightning.

The model was created with data collected over a 12-year period from 12 Swiss weather stations in cities and mountain areas. The data, related to four main surface conditions: air pressure, air temperature, relative humidity (湿度) and wind speed, was placed into a unique machine learning algorithm (算法), which compared it to records of lightning strikes. Researchers say the algorithm was then able to learn the conditions under which lightning happens.

The researchers test-ran the system several times. They found that the system made predictions that proved correct almost 80 percent of the time. “It can now be used anywhere,” the Swiss Federal Institute of Technology said in a statement.

The researchers plan to keep developing the technology in partnership with a European effort that aims to create a lightning protection program. The effort is called the European Laser Lightning Rod project. Scientists working on the project are experimenting with a laser technology that could someday control lightning activity, transferring lightning charges from clouds to the ground. They hope that such technology can one day be used as protection against lightning strikes. Possible uses could be at stations, airports or places where large crowds gather.