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

    Welcome to our school. You can do a lot of things here. Come and join us.

    Donald Trump has been known to do it in the middle of the night. Kim Kardashian has done it more than 22,000 times. Many people don't understand why you would want to do it at all.

    We're talking about tweeting and, unlike posting your entire life on Facebook, this social media activity demands a particular set of skills.

    Why use Twitter? It's a way to have a one-on-one virtual connection with your heroes and anybody who interests you. Likewise, you can share your life and views with an almost limitless number of people. And it all has to be done within the limit of 140 characters of text – plus photos, videos and links – which really helps you focus your mind.

    Katy Perry has the most Twitter followers, with 95.6 million of the micro-blogging site's 317 million monthly active users. Justin Bieber isn't far behind with 91.5 million, followed by Barack Obama and Taylor Swift with around 83 million each. The heaviest hitters of Twitter are pop stars, heroes of sport and other celebrities. But you don't need to be famous to create a buzz with the right tweets at the right time.

    In fact, Katy Perry is a great example of how to do it well. She has a bubbly tweeting style that mashes up chat about her tours and her music, insights into her emotional roller coaster over the US election, and playful descriptions about her daily life. "Done with my Christmas shopping", she tweeted, and posted a link to her Instagram page that featured crazy gadgets like a "pet emergency jacket" and a "chocolate donut camera".

    To get started on Twitter, pick a simple, memorable user name like @KatyPerry, post a short profile and choose a photo. Some tips: post your own photo (not a photo of your dog, it's not Facebook) and don't be an "egg person" – referring to the absent egg-shaped image when a user hasn't posted their own picture. In that case, Twitter won't get you any followers or respect.

    Then, it's time to start tweeting by sending your updates ("what's happening?") and following people. Building up an army of followers can take time. Generally, the more people you follow and the more you tweet, the more followers you'll get. To become a Twitter star, you need to carve out a reputation for posting original, eye-catching tweets on trending topics – and maximise your visibility by mastering the use of hashtags.

    Twitter Analytics will show you how your tweets are performing and who is following you – right down to their age category, country, income bracket, gender and interests. If your popularity is flagging and your Twitter ego is keeping you awake at night, you can turn to the business of buying thousands of "followers" from online sites. But do be ware – there may be a lot of fake profiles in there and, at the end of the day, it'll feel like paying a crowd of people you don't know to come to your birthday party.

    Happy tweeting!

    The European Union(EU) is an organization of European countries. The countries are independent and are governed in different ways. In the United Kingdom, for example, the head of state is a king or queen. In France, on the other hand, the head of state is a president. But each of them sends representatives to European Parliament, which has some control over what happens in each of the member countries.

    The idea of the EU began in the 1950s. The first members were France, Germany, Belgium, Luxembourg, the Netherlands and Italy. Little by little, the number increased during second half of the twentieth century. By the year 2000, there were 15 member countries. The new countries were Austria, Denmark, Finland, Greece, Ireland, Portugal, Spain, Sweden and the United Kingdom.

    In 2004, the EU increased to 25 members. The Czech Republic, Estonia, Hungary, Latvia, Lithuania, Poland, the Slovak Republic and Slovenia, plus the Mediterranean islands of Cyprus and Malta all became members. The expanded EU has a population of more than half a billion people, twice as big as the population of the US.

    A large body of research has been developed in recent years to explain many aspects of willpower. Most of the researchers exploring self-control do so with an obvious goal in mind: How can willpower be strengthened? If willpower is truly a limited resource, as the research suggests, what can be done to make it stay strong?

    Avoiding temptation (诱惑) is an effective method for maintaining self-control, which is called the "out of sight, out of mind" principle. One recent study, for instance, found office workers less attracted to candy in the desk drawer than that on top of their desks, in plain sight.

    The research suggesting that we possess a limited reservoir of self-control raises a troubling question. When we face too many temptations, are we to fail? Not necessarily. Researchers don't believe that one's willpower is ever completely exhausted. Rather, people appear to hold some willpower in reserve, saved for future demands. The right motivation allows us to tap into those reserves, allowing us to carry on even when our self-control strength has been run down. High motivation might help overcome weakened willpower-at least to a point.

    Willpower may also be made less vulnerable (脆弱) to being exhausted in the first place. Researchers who study self-control often describe it as being like a muscle that gets tired with heavy use. But there is another aspect to the muscle comparison, they say. While muscles become exhausted by exercise in the short term, they are strengthened by regular exercise in the long term. Similarly, regular practices of self-control may improve willpower strength.

    The evidence from willpower-exhaustion studies also suggests that making a list of resolutions on New Year's Eve is the worst possible approach. Being exhausted in one area can reduce willpower in other areas, so it makes more sense to focus on a single goal at a time. In other words, don't try to quit smoking, adopt a healthy diet and start a new exercise plan at the same time. Taking goals one by one is a better approach. Once a good habit is in place, Baumeister says, you'll no longer need to draw on your willpower to maintain the behavior. Eventually healthy habits will become routine, and won't require making decisions at all.

    Chinese scientists recently have produced two monkeys with the same gene, Zhong Zhong and Hua Hua, using the same technique that gave us Dolly the sheep. These monkeys are not actually the first primates(灵长类)to be cloned. Another one named Tetra was produced in the late 1990s by embryo(胚胎)splitting, the division of an early-stage embryo into two or four separate cells to make clones. By contrast, they were each made by replacing an egg cell nucleus(卵原子核)with DNA from a differentiated body cell. This Dolly method, known as somatic(躯体的) cell nuclear transfer(SCNT), can create more clones and allows researchers greater control over the edits they make to the DNA.

    Success came from adopting several new techniques. These included a new type of microscopy(显微术) to better view the cells during handling or using several materials that encourage cell reprogramming, which hadn't been tried before on primates. Still, the research process proved difficult, and many attempts by the team failed. Just two healthy baby monkeys born from more than 60 tested mothers. This leads to many researchers' pouring water on the idea that the team's results bring scientists closer to cloning humans. They thought this work is not a stepping stone to establishing methods for obtaining live born human clones. Instead, this clearly remains a very foolish thing to attempt, and it would be far too inefficient, far too unsafe, and it is also pointless.

    But the scientists involved emphasize that this is not their goal. There is now no barrier for cloning primate species, thus cloning humans is closer to reality. However, their research purpose is entirely for producing non-human primate models for human diseases; they absolutely have no intention, and society will not permit this work to be extended to humans. Despite limitations, they treat this breakthrough as a novel model system for scientists studying human biology and disease.