There's no doubt that man is the smartest. But do you know what other animals are smart, too?

    Dolphins

    Dolphins are very smart. Most of the “tricks” they're taught to do are actually behavior they would engage in on their own. They love to play, race and generally enjoy their life to the fullest. They speak a language we have yet to completely understand and like all civilized creatures, dolphins' mothers always provide their young children with guidance and possibly, love.

    Great apes

    The great ape family primarily consists of gorillas, chimpanzees and orangutans. Their brain chemistry is so similar to humans' that NASA once used chimpanzees in place of astronauts during many dangerous missions. Gorillas have been taught sign language and orangutans exist in complex familial relationships.

    Elephants

    Everyone has heard the phrase “an elephant never forgets”. Elephants establish long-term friendships, recognizing and remembering their friends years later. If an elephant comes upon a fallen friend, it has even been known to feel sad.

    Parrots

    As proved by this list, parrots are very smart. They are also the only animals listed that can actually hold a conversation. Some parrots know hundreds of words by imitating humans. The birds are also capable of remembering words and using them intelligently in response to situations.

    A Samoan airline says that it is the world's first carrier to charge passengers by their weight. Samoa Air, which opened in 2012, asks passengers to give their personal weight during booking, which is then charged according to the length of a flight. The customers will also be weighed just before they board the plane.

    "It is believed that all people throughout the world are the same size," Samoa Air CEO Chris Langton said. "Airplanes always run on weight, not seats."

    "There is no doubt in my mind that this is the concept of the future. This is the fairest way of your travelling with your family or yourself."

    Though the airline introduced the plan last November, it caught people's attention last week when the carrier began international flights to neighboring American Samoa.

    Almost at the same time, a Norwegian economist, Bharat Bhatta, published a report suggesting that airlines should charge obese passengers more.

    The Pacific Islands contain some of the world's most common countries for obesity, many ranking in the top 10, according to the World Health Organization (WHO). Samoa is ranked number four, with 59.6 percent of the population considered obese, said the most recent WHO report.

    According to Samoa Air's latest schedule, the airline charges up to $0.57 per kg for flights in Samoa and $1.03 per kg for its only international flight to American Samoa, around 250 miles.

    Children under 12 are charged 75 percent of the adult rate, with fares also based on weight. Any overweight baggage is calculated at the same rate as the passenger's personal weight.

    The plan could actually prove cheaper in some cases, such as for families travelling with small children, and Langton said customer reaction has mainly been "amazingly positive".

    The idea of charging passengers by weight has been hotly discussed before, and in the US some airlines require those who do not fit into a seat comfortably to buy a second seat.

    When we think of a generation gap we usually think of conflicting tastes in music, or pastimes. But now the generation gap is handwriting. After one teacher in Tennessee discovered that she had students who couldn't read the assignments she was writing on the board, she posted it on the Internet saying handwriting should be taught in schools.

    Opponents claim that handwriting has become out of time in our modern world. Typed words have become a primary form of communication. Once a practical skill, handwriting is no longer used by the vast majority of Americans. It is no longer taught in schools, and some claim that the time that it would take to teach it could be put to better use, for instance, by teaching the technical skills.

    But even in today's world there are still plenty of reasons to pick up a pen and apply it to paper. Many American institutions still require original signatures, for instance, signing for a registered letter and buying a house. And original signatures are much more difficult to forge（伪造）than their digital counterparts. There is also strong evidence that writing by hand is good for the mind. It activates a different part of the brain, and improves fine moving skills in young children. People also tend to remember what they write by hand more than what they type, and the process of writing by hand has been shown to stimulate ideas. Not only that, studies have shown that kids who write by hand learn to read and spell earlier than those who don't. Not to mention, handwriting is pleasing, as is evidenced by the fact that no one has ever typed a love letter. And handwriting remains popular as an art form.

    Yes we live in a modern world, but we live in a modern world that is based on fundamental values.

    Have you ever taken a test that you thought you could have passed easily, only to make some silly mistakes that really hurt your grade? More than a few students have done that. And some seem to do it over and over again.

    There are several problem areas that can cause students to goof up or do poorly in a test that they could have passed.

    Some students can become overconfident in their knowledge of the subject matter. They think they know the material better than they actually do. It is easy for students to misjudge their own knowledge, and when they realize that they don't know the material, it is too late.

    What happens more often, though, is that some students feel they are smart enough to be able to guess their way through a test. So they don't bother studying the material. They are overconfident in their ability to figure things out.

    In either case, overconfidence can result in lower grades in tests. Does this apply to you?

    Another thing that can happen is that students underestimate (低估) the difficulty of the test. They expect an easy test, but the teacher throws in a real tough test that they haven't prepared for. Sometimes the teacher may cover material in the test that students weren't expecting. That can happen, especially if you weren't paying attention in class.

    Finally, there are students who don't feel that getting a good grade is important to them, so they don't bother to study or even try to do well. Such students may be trying to punish their parents, have a poor image of themselves, or are just plain foolish. Hopefully, you are not one of these students.

    I was on my way home from work, cutting through the Bryant Park. On that day, the sun seemed to set faster than usual, and suddenly I found myself walking in the dark. I was less than half a mile from my apartment, but the path would lead me over a bridge, across train tracks, and through an unlit underpass.

    Then I heard him – a stranger running alongside me, partly obscured(遮掩) by the bushes. My mouth went dry; my legs felt like water. But I didn't pick up my pace – instead, I stopped, turned, and faced him. He came out of the bushes and said he'd been watching me "for a long time".

    As he walked beside me, I guided us towards the edge of the park. When we reached the bridge, a train rumbled(轰鸣着缓慢行进) past, and he seized the moment, attacking me with a knife around my throat. The self-defense skills I had learned years before kicked in, and I pushed my finger into his eye, hard. And then came the shock: That didn't frighten him away. My mind flashed back to a tip from an old guitar teacher: "Press the strings like you're squeezing a flea(跳蚤)." I put all my strength into that finger, and finally he let go.

    I was shaking with fear, but I looked him straight in the eye and began to back away. I turned to run the hell out of there, but then I remembered another self-defense lesson: Never run, because then you're a target. So I walked away alone – through the dark tunnel as I dialed 911 with trembling fingers. If you ever find yourself in this situation, use these self-defense skills that you already know. They can really make all the difference to you.

The periodic table of elements is a common sight in classrooms，campus hallways and libraries. The mode periodic table arranges the elements by their atomic numbers and periodic properties（周期性）. Several scientists worked over a century to assemble the elements into this format. 

In 1789，French chemist Antoine Lavoisiertried grouping the elements as metals and nonmetals. Forty years later，German physicist Johann Wolfgang Dobereiner observed similarities in physical and chemical properties of certain elements. He arranged them in groups of three in increasing order of atomic weight and called them triads，observing that some properties of the middle element，such as atomic weight and density，approximated the average value of these properties in the other two in each triad. 

A breakthrough came with the pu blication of a revised list of elements and their atomic masses at the first international conference of chemistry in Karlsruhe，Germany，in 1860. They concluded hydrogen would be assigned the atomic weight of 1 and that the atomic weight of other elements would be decided by comparison with hydrogen. For example，carbon，being 12 times heavier than hydrogen，would have an atomic weight of 12. 

In 1869，Russian chemist Dmitri Mendeleev created the framework that became the moder periodic table，leaving gaps for elements that were yet to be discovered. Mendeleev predicted the properties of some undiscovered elements and gave them names such as"eka-aluminum"for an element with properties similar to aluminum. Later "eka-aluminum"was discovered as gallium. 

German chemist Lothar Meyer produced a version of the periodic table similar to Mendeleev's in 1870. He left gaps for undiscovered elements but never predicted their properties. The Royal Society of London awarded the Davy Medal in 1882 to both Mendeleev and Meyer. The later discovery of elements predicted by Mendeleev verified（证实）his predictions and his periodic table won universal recognition. In 1955 the 101st element was named mendelevium in his honor. 

On UNESCO website，it wrote，"The Periodic Table of Chemical Elements is more than just a guide or catalogue of the entire known atoms in the universe；it is essentially a window on the universe，helping to expand our understanding of the world around us. "