It's a popular belief that a fish's memory lasts for only seven seconds. It may seem sad to think that they don't remember what they've eaten or where they've been, and they don't recognize you or any of their friends — every moment in their life would be like seeing the world for the first time.

    But don't be so quick to feel sorry for them. A new study has found that fish have a much better memory than we used to think. In fact, certain species of fish can even remember events from as long as 12 days ago.

    In the study, researchers from MacEwan University in Canada trained a kind of fish called African cichlids to go to a certain area of their tank to get food. They then waited for 12 days before putting them back in the tank again.

    Researchers used computer software to monitor the fish's movements. They found that after such a long break the fish still went to the same place where they first got food. This suggested that they could remember their past experiences.

    In fact, scientists had been thinking for a long time that African cichlids might have a good memory. An earlier study showed that they behaved aggressively（挑衅地） in front of certain fish, perhaps because they remembered their past “fights”. But until the latest findings, there was no clear evidence.

    Just as a good memory can make our lives easier, it also plays an important part when a fish is trying to survive in the wild.

    “If fish are able to remember that a certain area contains safe food, they will be able to go back to that area without putting their lives at risks,” lead researcher Trevor Hamilton told Live Science.

    For a long time, fish were placed far below chimpanzees, dolphins and mice on the list of smart animals. But this study has given scientists a new understanding of their intelligence.

    Are you carrying too much on your back at your back at school? I'm sure lots of children of your age will say “Yes”. Not only the students in China have this problem, but children in the United States also have heavy school bags.

    Doctors are starting to worry that younger and younger students are having back and neck problems as a result of school bags being too heavy for them.

    “It's hard for me to go upstairs with my bag because it's so heavy,” said Rick Hammond, an 11-year-old student in the US.

    Rick is among students who have common school bags with two straps（带子）to carry them, but many other students choose rolling（有滚轮的）bags.

    But even with rolling bags, getting up stairs and buses is still a problem for children. Many of them have hurt their backs and necks because of the heavy school bags.

    But how much is too much? Doctors say students should carry no more than 10% to 15% of their own body weight.

    Scout Batch, a back doctor, said children under Grade 4 should stay with 10%. But it is also important that older children don't stay with over 15%, because their bodies are still growing.

    “Children are losing their balance and falling down with their school bags,” he said.

    Parents and teachers are starting to tell children to only take home library books they will be reading that night. Some teachers are using pieces of paper or thin workbooks for students to take home.

    One of the best answers is, as some children said, to have no homework at all!

    The days of the hunter are almost over in India. This is partly because there is practically nothing left to kill, and partly because some steps have been taken, mainly by banning tiger-shooting, to protect those animals which still survive.

    Some people say that Man is naturally a hunter. I disagree with this view. Surely our earliest forefathers, who at first possessed no weapons, spent their time digging for roots, and were no doubt themselves often hunted by meat-eating animals.

    I believe the main reason why the modern hunter kills is that he thinks people will admire his courage in overpowering dangerous animals. Of course, there are some who truly believe that the killing is not really the important thing, and that the chief pleasure lies in the joy of the hunt and the beauties of the wild countryside. There are also those for whom hunting in fact offers a chance to prove themselves and risk death by design; these men go out after dangerous animals like tigers, even if they say they only do it to rid the countryside of a threat. I can respect reasons like these, but they are clearly different from the need to strengthen your high opinion of yourself.

    The greatest big-game hunters expressed in their writings something of these finer motives. One of them wrote.

    “You must properly respect what you are after and shoot it cleanly and on the animal's own territory(领地). You must fix forever in your mind all the wonders of that particular day. This is better than letting him grow a few years older to be attacked and wounded by his own son and eventually eaten, half alive, by other animals, Hunting is not a cruel and senseless killing - not if you respect the thing you kill, not if you kill to enrich your memories, not if you kill to feed your people.”

    I can understand such beliefs, and can compare these hunters with those who hunted lions with spears(矛) and bravely caught them by the tail. But this is very different from many tiger-shoots I have seen, in which modern weapons were used. The so-called hunters fired from tall trees or from the backs of trained elephants. Such methods made tigers seem no more dangerous than rabbits.

    Only about 30 percent of people in the US know how to perform CPR (心肺复苏术). Recently, a 9-year-old boy showed a Georgia woman how to perform CPR on her newborn baby.

    Susanna Rohm said she had experienced a parent's worst nightmare (噩梦) — her 2-month-old son, Isiah, was not breathing. "I noticed he looked pale. I looked at his arms and his legs and they were limp (无力的)," Rohm told a local newspaper. "Then I noticed that he looked like he wasn't alive." Indismay, she dropped and broke her cellphone. Rohm had to run into the street, screaming for help.

    "I had him in my arms and screamed over and over. Then I ran outside. I saw two boys playing across the street, and I yelled, 'Go and ask your parents to call 911,'" Rohm said. But the two boys were able to do more than that. Nine-year-old Ethan Wilson took action, showing Rohm how to perform CPR on little Isiah while ten-year-old Rocky Hurt helped as well.

    Rocky said he had learned the CPR technique from a poster in a health class at their school, Sedalia Park Elementary. "I was thinking we'd better give her a helping hand instead of getting scared," Ethan said. "I told her to push on the baby's chest five to ten times a minute with only two fingers, tilt back the baby's head, plug the baby's nose and breathe into the baby's mouth," Ethan said in an interview.

    At last, Isiah began crying and was breathing again. He spent two nights in a local hospital. "If the little boy hadn't shown me what to do right there, my baby would probably not be alive right now," Rohm said.

When I was in the eighth grade, my class was assigned (指派) to be friends with the second-grade kids. I got this little girl named Shelley. The first time I saw her, she was silent and cold. She was small for her age, and she didn't play with the other kids in her class.

I tried all kinds of things to get her to talk to me. I bought her toys, crayons and candies. But try as I might, nothing worked. One time, I gave her a coloring book and said, "Shelley, now you can color at any time."

Shelley looked at the coloring book and then looked up at me, and finally looked away. By that, I didn't know how I was going to get through to the little girl, but I knew I wouldn't give up on her.

One Friday, I decided to tell her a story about my childhood. I told her that I felt lonely when I was with my classmates, and how I thought only my teachers liked me. I also told her that every day was a battle(战役) for me and that I fought back tears so people wouldn't know how much I was hurting.

She sat there just listening, trying to decide whether I was lying or not. Finally, when my story ended, there were tears in her eyes. And then she did the unthinkable, She said, "Thank you." From then on, Shelley was a different little girl. She started smiling and talking with other kids.

Looking back at this,I'm in awe(惊叹), because all I did was to help her realize that she wasn't alone. I didn't ask her to tell her story, because her story is my story,