1 . Do you know about bioplastic (生物塑料)? It is a kind of plastic. But it is different. Normal plastic is made from chemical materials and takes a very long time to degrade (降解). But bioplastic is good for the environment. It is made by using bacteria (细菌) to process natural sources like vegetable oils, corn or sugar. It can degrade more easily.

But there is a problem with bioplastic. The “food” that bacteria eat is also what we eat. This means that bacteria are competing against humans for the same resources.

Now scientists have found a new way to make bioplastic using two kinds of bacteria and sunlight, according to Newsweek.

One of the bacteria is called synthetic cyanobacteria (合成蓝藻), which can use sunlight to produce sugar. The other kind is Halomonas boliviensis (玻利维亚盐单胞菌), which lives in the salty waters of Bolivia. It eats the sugar that the first bacteria produce and then it can produce polymers (聚合物). Polymers are used to create bioplastics. The way the bacteria store polymers is similar to how humans store fats.

Producing bioplastic with these two bacteria has many advantages. It is 20 times faster than the normal way we produce bioplastic. Also, using these two bacteria saves resources.

First, producing large amounts of bioplastic requires corn and sugar, which are used to feed normal bacteria. And growing corn and sugar needs farmland. But these two special bacteria can just use sunlight. The land that is saved can be used to grow food for humans.

Besides, this process doesn’t need rich land or clean water at all, scientists said to Newsweek.

The next challenge scientists face is that they want to put their lab research into real-world practice. By doing this, bioplastic made with these two bacteria can be widely produced in the future.

5 . How exercising changed their life

6 . A five-­year-­old dog named Kelsey has been praised as a hero for helping to save the life of her owner who slipped in the snow and broke his neck.

The man, Bob, was alone when he left his farmhouse on New Year’s Eve to collect firewood.Expecting a journey of only several meters, Bob was wearing just long johns (衬裤), a shirt and slippers when he went outside, although the temperature was around －4℃.

After the accident, he was unable to move in the snow. Fortunately, Kelsey came to his assistance.

“I was shouting for help, but my nearest neighbor is about 400 meters away, and it was 10:30 p. m.,” Bob explained. “By the next morning, my voice was gone and I couldn’t yell for help, but Kelsey didn’t stop barking.”

Kelsey’s companion kept him warm by lying on top of him. She licked his face and hands to keep him awake. “Kelsey kept barking but never left my side,” Bob recalled. “I knew I couldn’t give up and that it was my choice to stay alive.”

Bob spent 20 hours in the freezing cold. When he finally lost consciousness, his dog kept barking. Finally, hearing the barking, Bob’s neighbor discovered him at 6:30 p. m. on New Year’s Day and called the emergency services at once. When Bob arrived in hospital, his body temperature was below 21℃. However, doctors were surprised to find that he didn’t have any frostbite (冻疮). They believed it was because of Kelsey’s determination to keep him warm. Dr. Chaim Colen, the doctor who treated Bob, said, “His dog really saved him.He was very fortunate.”

Bob said he was very grateful to both Dr. Colen and his Kelsey. “They saved my life. They are truly heroes!”

7 . A quick walk onto a frozen pond (池塘) could have been a disaster for these two boys.

Cruz Genet, 11, and Anthony Skopick, 10, couldn’t agree more. Were the birds out on the ice ducks or geese? There was only one way to find out. So on a cold January evening last year, the two friends walked onto the frozen pond near their homes to get a better look.

First, they threw a rock onto the ice to test it. Believing the ice would hold their weight, Anthony took a few steps, and then he crashed through the seemingly frozen surface. “There was no sound and no crack”, he told the reporter. “I just fell through immediately.”

Cruz rushed to help his frightened friend. And he fell in the pond, too. Cruz managed to lift himself out of the water and onto a harder part. He then carefully worked his way toward Anthony, but he fell in the pond again. This time, he couldn’t get out.

The two boys were in icy cold water and quickly losing feeling in their limbs (四肢). Cruz was sure that he was going to die.

Anthony’s older sister had seen the boys fall through the ice and started shouting for help. John Lavin, a neighbor driving nearby on his way to the store, heard her. He quickly pulled over. Seeing the boys, he took a nearby buoy (浮标), kicked off his shoes, and ran into the water. Lavin made his way to Cruz and Anthony and drew them back to land. They were taken to hospital, where doctors discovered that their five-minute stay in the water had lowered their body temperature nearly ten degrees.

Luckily, the boys have fully recovered, though they are still a little awestruck (敬畏的) by their fearless neighbor. “Just to think,” says Cruz, “if he hadn’t been there, I could have died.”

8 . Playing sports is a lot of fun. Getting hurt is not.    1    

Wear protective equipment.

The equipment you wear depends on the sport you play. Helmets (头盔) are the most common protective equipment. They protect your head while you’re playing football, baseball, softball, and so on.

Warm up.

    2     Doing some stretches (伸展) can get you prepared to hit the field. By warming up, you get yourself ready to play. Practicing a sport helps keep you safe, too.

Know the rules of the games.

Traffic lights help prevent crashes between many cars that run on the road together. This works because drivers know the rules and follow them—at least most of the time.    3     When players know the rules of the game, fewer injuries happen. For example, you know that in soccer you can’t come from behind, crash into a player’s legs, or steal the ball. It’s legal and safer to go after the ball rather than the player.

    4    

This is a really important one. If you love sports, you may want to get back in the games, even after an injury. But playing when you’re hurt is a bad idea.    5    

Now you know how to prevent sports injuries. If you follow these rules, you can stay safer while you are playing sports.

9 . How to deal with your homework

Write it down.     1     Always be sure to write down all the homework so you won’t forget anything.

Create a homework station. Find somewhere comfortable and quiet to do your homework.     2     It will take twice as long to get the homework done. Shut off your cell phone, log off (退出) your computer (unless you need it for your homework) and close the door.

Do homework as early as possible. Don’t leave homework to the last minute.     3     The earlier you start your homework, the sooner you will finish! Do all your homework as early as you can, so you don’t have a pile of ( 一 堆 ) homework the next day.

    4     Think about how long it will take you to complete homework for each subject. For example: English-ten minutes, science-ten minutes, math-forty minutes, history-twenty minutes.

Treat yourself. You can easily get tired by sitting through an hour or two of homework without stopping. Once you finish homework for a subject, take a small break (no more than 15 minutes). Either taking a walk or finding something to eat will do. But do not turn on the TV, or you’ll never go back to your study.     5    

10 . A teenager needs to have a sense of independence in their life to feel secure (安全的). To some teenagers independence means a lot to them, and I think that some parents don’t allow their teenagers enough independence.

Independence has something to do with freedom. Some kids are not allowed to go anywhere alone, and the only thing their schedule includes is going to school, coming home, going to sleep, and repeating the process the next day. Parents tend to be afraid that their kids can get hurt if they go outside into the world. But if parents control their kids too much, they may never learn to live on their own. The best way for a teenager to learn lesson is through experience. I think it is beneficial for teenagers to have freedom.

Teenagers’ lack of freedom can also stop them from having good friendship at school. Some might say this is a good thing, because it helps them focus more on their school work. I argue that this can only discourage them not to do their school work. Some parents do not allow their children to be around their friends outside the school, thinking that this will get them into trouble. But I don’t think so. Instead, isn’t this a good reason for parents to get their children a cellphone? Cellphones allow teenagers to stay in touch with their parents, and communicate with friends.

Privacy is another issue between parents and their teenagers. Teenagers tend to enjoy relaxation by themselves in their own room. This also gives them a sense of independence. It often annoys teenagers when their parents enter their room when they are not home. I know that my mom always goes in my room when I’m not home, and this has brought me to the point where I have asked many times to get a lock on my door.