Memory, they say, is a matter of practice and exercise. If you have the wish and really made a conscious（自觉的）effort, then you can quite easily improve your ability to remember things. But even if you are successful, there are times when your memory seems to play tricks on you.

    Sometimes you remember things that really did not happen. One morning last week, for example, I got up and found that I had left the front door unlocked all night, yet I clearly remember locking it carefully the night before.

    Memory “trick” work the other way as well. Once in a while you remember not doing something, and then find out that you did. One day last month, for example, I was sitting in a barber（理发师）shop waiting for my turn to get a haircut, and suddenly I realized that I had got a haircut two days before at the barber shop across the street from my office.

    We always seem to find something funny and amusing（有趣的）in incidents caused by people's forgetfulness or absent-mindedness. Stories about absent-minded professors have been told for years, and we never got tired of hearing new ones. Unfortunately, however, absent-mindedness is not always funny. There are times when “trick” of our memory can cause us great trouble.

    Most people agree that honesty is a good thing. But does Mother Nature agree? Animals can't talk, but can they lie in other ways? Can they lie with their bodies and behavior? Animal experts may not call it lying, but they do agree that many animals, from birds to chimpanzees, behave dishonestly to fool other animals. Why? Dishonesty often helps them survive.

    Many kinds of birds are very successful at fooling other animals. For example, a bird called the plover sometimes pretends to be hurt in order to protect its young. When a predator（猎食动物）gets close to its nest, the plover leads the predator away from the nest. How? It pretends to have a broken wing. The predator follows the “hurt” adult, leaving the baby birds safe in the nest.

  Another kind of bird, the scrub jay, buries its food so it always has something to eat. Scrub jays are also thieves. They watch where others bury their food and steal it. But clever scrub jays seem to know when a thief is watching them. So they go back later, unbury the food, and bury it again somewhere else.

    Birds called cuckoos have found a way to have babies without doing much work. How? They don't make nests. Instead, they get into other birds' nests secretly. Then they lay their eggs and fly away. When the baby birds come out, their adoptive parents feed them.

    Chimpanzees, or chimps, can also be sneaky. After a fight, the losing chimp will give its hand to the other. When the winning chimp puts out its hand, too, the chimps are friendly again. But an animal expert once saw a losing chimp take the winner's hand and start fighting again.

    Chimps are sneaky in other ways, too. When chimps find food that they love, such as bananas, it is natural for them to cry out. Then other chimps come running. But some clever chimps learn to cry very softly when they find food. That way, other chimps don't hear them, and they don't need to share their food.

    As children, many of us learn the saying “You can't fool Mother Nature.” But maybe you can't trust her, either.

    A new tool of communication called the “drift diary” is doing the rounds among young college graduates.

    The “drift diary”, like those ancient paper messages put into a bottle left to drift on the high seas to reach hundreds of miles away, connects lonely hearts.

    The “drift diary” was first started by a Beijing woman, who goes by the Net name Little S, in 2007. It has become the preferred tool of communication among youngsters afraid to reveal their innermost self to peers, but wanting to share their lives with others.

    The way it works is that the initiator（发起人）of the diary mentions it on popular  Internet forums such as Tianya and Douban. Those wanting to react or otherwise add to the diary then send their real names and addresses to the initiator via e-mails or text messages.

    The numbers in one group are usually restricted to between 30 and 50. The diary then passes on to another by express delivery or personal handover. The diary writers are mostly anonymous but if they wish to reveal their identity they can do so by posting their contact information at the end of their postings.

    The diary writers add not just words but also decorate the plain notebooks with cartoons, drawings or even dress it up with a ribbon or a new cover. Interesting experiences, travel journals, the simple joys of everyday living or sweet recollections of childhood, all find a place in these diaries. Most often, though, the writers set down their frustrations and predicaments.

    It usually takes one year for a diary to return to the initiator. The last recorder is the luckiest one, with access to all previous entries, while others can request photocopies of these from the diary's initiator.

    The world's first-known nursery for baby giant manta rays(蝠鲼) has been discovered hidden away in the Gulf of Mexico, the place of 70 miles off the coast of Texas, after studying decades of giant manta ray data from the area by the scientists.

    Where the baby manta rays grow up has long troubled scientists, as they are rarely spotted in the four to five years it takes them to become adults, when they can often grow to more than 20ft wide.

In the study Mr Stewart and colleagues describe a reef (暗礁)—filled with mantas of all ages—where the sea floor runs down into deeper water. He said "We think they may be feeding on specific types of zooplankton(浮游生物) there, then migrating up toward the surface, where we saw them. They might be hanging around the banks because it could be a little safer than open water. We've seen them so rarely that we know very little about these baby manta rays. We don't know how far they move, or exactly what they feed on, or all of the habitats these access.”

    Giant manta rays are listed as species dying out by protectors, although actual population numbers of the mysterious "gentle giant" are hard to calculate. Sightings of the closely-related reef manta, however, have dropped by 90 percent in regions of southeast Asia in the past decade, according to a study.

    Fishing is considered the biggest threat to giant manta numbers, both intentional and accidental. Their gill plates(腮下肉)- the parts through which they filter(过滤) their food from seawater-are sold in China for medical purposes, while they often end up as something caught by mistake due to their huge wings.

In an attempt to fight with the nation's food wastage problem, Denmark has opened the world's first supermarket that sells expired(过期的) or damaged products. Ever since the grand opening in Copenhagen last Monday, people have been lining up outside WeFood for a chance to purchase discounted items that would otherwise have ended up in the trash because of damaged packaging or very short use—by dates. Food, cosmetics, and other household items at WeFood are priced at least 30 to 50 percent lower than at regular stores.

    “WeFood is the first supermarket of its kind in Denmark and perhaps the world, as it is not just aimed at low-income shoppers but anyone who is concerned about the amount of food wastage produced in the country,” said project head Per Bjerre. “Many people see this as a positive and correct way to approach the issue.”

    While Denmark alone is estimated to waste about 700,000 tons of food every year, the United Nations has stated that globally, food waste amounts to 1.3 billion tons. About 795 million people in the world are undernourished. Denmark, however, has adopted several measures to clean up its act, wasting 25% less food than it did five years ago.

    The WeFood project is a collaboration between The Food Bank and charity DanCurch Aid. Together they raised nearly $150.000 over the past year through crowdfunding. They also had to face many obstacles while convincing the government to permit the sale of expired food. They were finally allowed to carry out the project, and the store is now run only by volunteers. Profits are used to fund DanChurch Aid's other projects in developing nations like South Sudan and Bangladesh.

    Provided WeFood's remains popular in the long term and if it is able to maintain its food deliveries, DanChurch Aid plans to open multiple branches across Denmark.

    Most animals on land are known to us, but many living things underwater are not. Now let's get to know some of them.

    Sea cucumber

    Sea cucumber are strange animals living at the bottom of the sea. They wear brown or pale green coats with many sticks up. When summer comes, they stay deep to sleep because they are afraid of heat. And when it is autumn, they move to shallow (浅的) water and get their food.

    Pike

    The pike is a kind of freshwater fish. They are good swimmers and like swimming near boats, waiting to be fed. They have sharp teeth to catch fishes. When they are young, they live in groups. However, when they grow up, they prefer to live alone.

    Cuttlefish

    A cuttlefish can swim quite fast, so it is also called rocket (火箭) fish. It has eight arms and two feelers on its head, just around its mouth. It ejects ink (喷墨) when it is in danger. Its meat is delicious, and it is often the first choice for many people.

    Octopus

    An octopus has long arms, with which to catch food and protect itself. When it is sleeping, one or two of its arms are still on duty, keeping moving. Once it feels something dangerous, it can wake up at once to take action.