Dolphins(海豚) live in a dark underwater world. It's often impossible to see each other or anything else around them, so sound plays an important role in their survival. To communicate with each other, dolphins produce all kinds of sounds.

    Only other dolphins understand what the sounds mean. Scientists haven't uncovered their secret communication, except for one kind of whistle. It might last less than a second, but this whistle is a big deal. Why? Because these whistles are actually names of dolphins - and every dolphin has one. Scientists call these sounds a “signature whistle.” When other dolphins hear the whistle, they know which dolphin is calling.

    Dolphins often hunt by themselves but still need to stay connected to the group. Since they can't always see each other, dolphins use their signature whistles to check in with other dolphins hundreds of yards away. “In coastal areas, dolphins exchange whistles even when they're a third of a mile apart,” says Greg Campbell, who studies animals. That means dolphins shout out to group members that might be nearly five football fields away.

    What's amazing is who names the baby dolphin. Not the mother. Not an auntie dolphin or another group member. Scientists believe the baby dolphin itself comes up with the signature whistle. Like human babies, a baby dolphin plays with sounds throughout its first year. While testing its sound skills, a baby dolphin is doing something amazing. It's creating or figuring out its signature whistle. How or why it chooses its signature whistle is not clear. Studies show that most of the time the signature whistle is nothing like its mother's or group members' whistles.

    When the baby dolphin is about a year old, its signature whistle is set. It repeats it often so the other dolphins learn to recognize it.

    Deciphering(破译) dolphin names is just the beginning of figuring out what dolphins communicate about. Do they chat about sharks? Discuss the tides? Maybe they even have a name for people. Someday scientists are to decipher the rest of dolphins' communication.

Visiting Joshua Tree National Park, California

    Joshua Tree National Park is nearly 800,000 acres (英亩) large and surrounds parts of the Mojave and Colorado Deserts in South-central California. Although barren at first sight, the park is full of wildlife and provides a variety of entertainment activities from hiking to climbing. Within a three-hour drive, Joshua Tree National Park takes at least a full day to visit.

Things to do

    Hiking opportunities within the park include several choices, from 12 self-guided nature routines to all-day back-country hikes.

    Joshua Tree NP has nine camping grounds, and back-country camping is also allowed.

    Rock climbing is a popular activity in the park, which has 10 mountains greater than 5, 000 feet in height.

When to visit

    Joshua Tree NP is open 365 days a year, although the best time to visit is October through April, when temperature is milder. The peak season is when the wild flowers bloom, and the summer months are the least crowded.

What to bring

    In addition to your camera and telescope, be sure to carry lots of water. Park and guiding maps can be picked up at any of the three visitor centers.

Fees

    Parking fees: You can buy a seven-day vehicle permit (周票) for $ 15, a single entry permit for $ 5, or Joshua Tree National Park annual (每年的) pass for $ 60.

Camping fees: They vary by camping ground

    One of the most important things in the world is friendship. In order to have friends, you have to be a friend. But how can you be a good friend at school?

    Listen — Listen when they are talking. Don't say anything unless they ask you a question. Sometimes it's not necessary for you to have anything to say; they just need someone to talk to about their feelings.

    Help them — If your friend is ever in need of something, be there to help them. You should try to put them first, but make sure you don't do everything they want you to do. Try to take an extra (额外的) pencil or pen with you to classes in case (以防) they forget one. Have a little extra money in your pocket in case they forget something they need.

    Be there for them — Try to make something for your friend to help make them feel better in hard times. Making cards and encouraging them are among the nicest things you can do for a friend. Marilyn Monroe, a famous U.S. actor, once said, “I often make mistakes. Sometimes I am out of control. But if you can't stay with me at my worst, you are sure not to deserve (值得) to be with me at my best.” Always remember this! If you don't want to stay with your friends when they're in hard times, then you don't deserve to be with them when they're having a good time!

    Make plans — Try to make plans with your friends. Go shopping, go for ice cream, have a party, go to a movie and so on. Take time to know each other even better by doing something you both enjoy. By planning things together, you both can have a good time. And you'll remember these things when you're all old!

    The Internet, social media, and smart phones allow you to learn many things.{#blank#}1{#/blank#}However, just like in the real world, not everyone online is your friend. Some may use these tools to send unpleasant messages to you, and some may use your information to do something bad. It's very important to know how to stay safe and have positive experiences online. Here are some tips for you.

    Be careful about friend or follower requests. When you have a friend or follower request, check the person's information first.{#blank#}2{#/blank#}Only accept friend or follower requests from people you have met in the real world. Don't chat with people you don't know or trust. This is a good way to keep you safe.

    Review location(定位) services on your phone and other mobile devices.{#blank#}3{#/blank#}They may put you in danger because others can find you easily. To make sure of your safety, turn off the "location services" or "locations settings" features on your mobile devices. Also turn off GPS for the camera, chat and other social media apps.

    {#blank#}4{#/blank#}Strong passwords (密码）should have some upper and lower-case letters, numbers and symbols. If you have a strong password, it'll be difficult for others to know it. Also, avoid having the same password for all your social and education accounts (账户). It is really not safe for your accounts.

    {#blank#}5{#/blank#}If someone sends unpleasant messages to you online, find someone you feel safe talking to. For example, you can talk to a parent, a teacher or a trusted adult and ask him to help report and block(屏蔽) the person. Don't try to do the same thing when others do something that hurts your feelings online.

A. Create strong passwords.

B. Try to get help when necessary.

C. Find out if he or she is someone you know.

D. Friend requests can tell a lot of information.

E. Talk to someone you find safe to talk to online.

F. They also allow you to talk with friends online.

G. Location services can tell others where you are.

Tips for Cooking on a Tight Schedule

    From my experience, there are three main reasons why people don't cook more often：ability, money, and time.{#blank#}1{#/blank#} Money is a topic I'll discuss another day. So today I want to give you some wisdom about how to make the most of the time you spend in the kitchen. Here are three tips for great cooking on a tight schedule：

    ⒈Think ahead. The moments when I think cooking is a pain are when I'm already hungry and there's nothing ready to eat .So think ahead of the coming week. When will you have time to cook？ Do you have the right materials already？{#blank#}2{#/blank#}

    ⒉Make your time worth it. When you do find time to cook a meal, make the most of it and save yourself time later on. Are you making one loaf of bread？{#blank#}3{#/blank#} It takes around the same amount of time to make more of something. So save yourself the effort for a future meal.

    ⒊{#blank#}4{#/blank#} This may surprise you, but one of the best tools for making cooking is to try new things. It gives you the chance to hit upon new ideas and recipes that can work well with your appetite and schedule. The more you learn and the more you try, the more ability you have to take control of your food and your schedule.

    Hopefully that gives you a good start.{#blank#}5{#/blank#} And don't let a busy schedule discourage you from making some great changes in the way you eat and live!

A. Try new things.

B. Ability is easily improved.

C. Make three or four instead.

D. Understand your food better.

E. Cooking is a burden for many people.

F. Let cooking and living simply be a joy rather than a burden.

G. A little time planning ahead can save a lot of work later on.

    The United States will introduce a new and comprehensive(综合的) exam for students who seek to study in American and other English-speaking countries, Xinhua News Agency reported from New York.

    The exam, which stands for a great change from the current English level test, was disclosed by Theresa Chang Wei Jen, associate director of the International Service of the US College Board, America's leading educational organization.

    The Advanced Placement International English Language (APIEL) will be offered for the first time throughout the world on May 10, 2002, said Jen.

    However, the APIEL is a strange title to most Chinese students, and it is unlikely to soon gain the similarity of other already existing exams, such as the TOEFL(Test of English as a Foreign Language), the GRE(Graduate Record Examination), or the IELTS(International English Language Testing System).

    "I have never heard of such a test and I would prefer the IELTS if I need another exam," said Xu Jingyan, a graduating student from Beijing University of Aeronautics and Astronautics, who wants to study in England and has already taken the TOEFL.

    Most of Xu's classmates have never heard of the APIEL. "The APIEL is designed for international students who wish to get university studies in English-speaking countries, including the United States, Britain, Canada, and Australia." said Jen.

    The APIEL has been adopted, said Jen, because the TOEFL can no longer accurately reflect the abilities of students of using the English language comprehensively in an academic environment. Xinhua reported that a fairly large number of foreign students who earned high scores in TOEFL exam turned out to be very ordinary educational performers after admission.

    Compared with the TOEFL, the APIEL measures a student's ability to read, write, speak and understand English through testing his or her skills in listening comprehension, speaking with accuracy(精确) and resourcefulness, and writing with clarity(清晰) and fluency, Jen said.