This column is part of a series on websites that are useful for English language learning.

Activities for ESL Students

    Includes various types of tests, exercises and puzzles designed to help people studying English as a second language（ESL）.The activities include grammar, vocabulary and idiom tests at easy, medium and difficult levels. The specially designed Chinese-English vocabulary tests can help Chinese memorize English words.

http://a4esl. org/

Interesting Things for ESL Students

    Contains a comprehensive list of audio clips（听力剪辑）from the Special English programs of Voice of America（VOA）.The list covers news of all kinds on VOA. The listening and vocabulary exercises and the word list designed with the clips will help English learners improve listening ability and increase vocabulary.

http://www.manythings.org/voa/

World-English

    This site provides a list of radio or TV channels offering English news clips. It includes the BBC radio program clips from England, CNN and ABC news clips from the US, and other news clips from other English-speaking countries. Click on the links and you will be taken to channels where you can listen to clips. This is a good way to practice listening.

http://www.world-english.org/listening.html

Listen to English

    Offers a large number of materials for English learners to practice listening. The materials include business English, English literature, history, movies, and politics. Students can improve their English while enjoying the beauty of the English of literature, songs, movies, and news in different countries.

http://eleaston.corn/listen, html

    Women are friendly．But men are more competitive．Why? Researchers have found it's all down to the hormone oxytocin （荷尔蒙催生素）．Although known as the love hormone, it affects the sexes differently．

"Women tend to be social in their behavior．They often share with others．But men lend to be competitive．They are trying to improve their social status," said Professor Ryan．

    Generally, people believe that the hormone oxytocin is let out in our body in various social situations and our body creates a large amount of it during positive social interactions （互动） such as falling in love or giving birth．

But in a previous experiment Professor Ryan found that the hormone is also let out in our body during negative social interactions such as envy．

    Further researches showed that in men the hormone oxytocin improves the ability to recognize competitive relationships, but in women it raises the ability to recognize friendship．

Professor Ryan's recent experiment used 62 men and women aged 20 to 37．Half of the participants（参与者）received oxytocin．The other half received placebo （安慰剂）．

    After a week, the two groups switched with participants．They went through the same procedure with the other material．

    Following each treatment, they were shown some video pictures with different social interactions．Then they were asked to analyze the relationships by answering some questions．The questions were about telling friendship from competition．And their answers should be based on gestures, body language and facial expressions．

    The results indicated that, after treatment with oxytocin, men's ability to correctly recognize competitive relationships improved, but in women it was the ability to correctly recognize friendship that got better．

    Professor Ryan thus concluded: "Our experiment proves that the hormone oxytocin can raise people's abilities to better distinguish different social interactions．And the behavior differences between men and women are caused by biological factors （因素） that are mainly hormonal．"

    Luke has always been my closest and constant companion these past five years. In fact, he is very friendly to me especially when I take care of other furry friends in our shelter.

    There have been a lot of forest fires during the summer season. Not far from our shelter, a forest caught fire during this hot summer. Luke rushed towards the forest where flames send out a terrible heat. There's no longer any hope at the moment to wait for Luke to come back to the shelter. In fact, I was waiting for the firemen to announce me his death in the forest. Suddenly, a fireman burst into my office and informed me that my dog Luke succeeded in saving four cats which were trapped by the flames. Luke seized the kittens, one by one moving them to a safe place. I immediately accompanied the fireman to the forest to pick up the rescued kittens, but Luke was not there. Then we heard the sound of a dog came from the forest barking furiously. The firemen followed the tracks of the dog until they found him barking loudly by the side of an injured fireman who was lying on the ground.

    That day, I was very proud of Luke for his two heroic actions. I paid a visit to the fireman accompanied with my adorable Luke. What a memorable scene when the fireman hugged Luke tightly to his chest!”One thousand thanks, Luke, for saving my life,” the fireman said.

    This true story of love and compassion shows us that pets are loving, caring and compassionate. We should love and protect them. Don't belittle them. Little animals can make enormous things for humans.

    Bats are the only mammals(哺乳动物) that can fly a great distance, but they have another ability. Many bats live a very long time for an animal of their size. European researchers are studying bats to understand why they lives0 long. They hope to make discoveries aimed at fighting the aging process in human beings.

    Last week, the group of scientists said they had identified important biological qualities in some bat species. The group studied bat chromosomes(染色体), a line of genes found in the nucleus(细胞核) of cells. The scientists were most interested in structures connected to the ends of the chromosomes. They are called telomeres(端粒), which protect the ends of chromosomes and shorten each time a cell divides. Scientists believe this shortening process causes cells to breakdown. They say this is what causes aging.

    The European researchers studied 493 bats from four bat species. The group used information that had been gathered over more than 60 years. Of these animals ，the greater mouse-eared bat generally lived the longest, an average of 37 years. The scientists said this and a related species, which are grouped together under the name Myotis, had telomeres that did not shorten with age. Another Myotis bat holds the record for oldest age, reaching 41years. The scientists' findings suggest that these bats cells have the ability to maintain and repair their telomeres. This, they said, helps guard against the aging process.

    Based on its body size, a bat like the greater mouse-eared bat would be expected to live four years. But, these mammals have been found to live nearly 10 times longer than that. The scientists found that only 19 species of mammals live longer than humans when their body size is considered. Eighteen of these are bats.

    It is true that world population is growing, but this is not the cause of our current and future global problems. Believing this will cause us to ignore the real problem and risk long-term damage to our planet.

    Let me start by explaining why overpopulation is a myth. For one thing, the UN Population Division regularly predicts population growth but provides a low variant (变量), medium variant, and high variant to factor in various possibilities. In the 2010 revision, their high variant suggests that the world population will be almost 16 billion in 2100, but the low variant predicts it will peak（达到顶峰） at 8 billion and decrease to just over 6 billion by 2100. In most cases, it is the low variant that has come true in the past, suggesting the same will be true of their future population predictions. In addition to this, the size of families is actually decreasing.

    For another, if the Earth is overpopulated, there needs to be insufficient (短缺) food, water, and space for humans to live. However, Indian economist Raj Krishna estimates that India alone is able to increase crop produce to the point of providing the entire world's food supply. The World Food Programme confirms that there is sufficient food grown to feed the world and there is the same amount of fresh water on the planet now as there was 10,000 years ago. So how is it possible that the number of people in the world is affecting our planet?

    Therefore, it is not an increase in population but an increase in consumption that is a severe threat. Materialism and overconsumption are facts of life for everybody in the western world, as possessions reflect a person's status in society and people strive to obtain happiness through owning the latest fashionable goods. Not only that, but waste is a common occurrence which has a huge effect on our resources. It is a sad truth that 80% of the world's resources are currently used by just 20% of the world's population.

    Our overconsumption must be addressed now to make our lives more sustainable and avoid continuing the terrible damage to the environment we are causing. The key is education. If we do not work towards this but instead focus on the wrong issue, we may find ourselves living on a planet that can no longer sustain human life.

    You have heard the words “that which does not kill you makes you stronger”. I have found it true. But I also believe in the philosophy that we are not defined (定义) by what happens to us, but by what we do when things happen to us.

    Some friends think we have had far more than our share of bad things occur, but I don't think bad things are shared. They are events that occur as the result of many aspects, sometimes far past our control or even knowledge of them. I am also a firm believer in the laws of unintended consequences — one event causes things that are quite unexpected, sometimes positive, sometimes not.

    So as I considered the question of “What motivates me?” and sought an answer, it struck me that I simply refuse to be defeated. I won't let life or events tear me down to the point at which I am no longer me, or simply stop being.

    In 2008, I battled three types of cancer, had four cancer operations, the firm I worked for closed without notice, my wife was in a horrible car accident, got laid off from her company, the economy devastated our life savings, … and that was for starters.

    We also lost two family members and my closest friend. He was the last person I would expect to pass away out of our friends. But a disease took hold of him 9 years earlier. His memorial service was filled with love, and many of us told about his joy of life, humor, his achievements, and the challenges he had overcome in his life — which were many and painful. He would not be defeated in his life either.

    Today, my wife and I are hand-in-hand, continuing trying to live our lives with dignity, although living it differently from the end of 2007.