In many high schools，there are strict rules about using mobile phones. If your phone rings in class，for example，the teacher will be very angry.
   Every mobile phone has a ringtone (铃声). It tells you that someone is calling you. Now，there is a ringtone called “mosquitotone (蚊子铃声)”. Using it，students can receive calls and text messages (短信) in class but the teacher will not realize what is happening. How?
   Mosquitotone has a special sound. Only children and teenagers can hear it. As we get older，we are unable to hear some sounds with high frequencies (频率). As a result，a child or teenager can hear the mosquitotone ringtone, but it's_inaudible_to someone 20 or older.
   But sometimes，people over 20 can hear the ringtone. One British student's phone uses mosquitotone. In class，the student's phone rang. The 32­year­old teacher looked at the student and became unhappy. “I heard that. You know the rule：no mobile phone in class.”
   Not all the students are interested in mosquitotone. Jerry Jones，a high school student of 17，says，“Using mosquitotone too often is bad for our hearing. I may use it for pleasure，but not in class. It's unfair to the teachers！”
   What do parents think of mosquitotone？“I think it is perfect for places like movie theaters，” says Connie Neeson,44.“Think about it. Yon're watching a film and someone's mobile phone rings. Mosquitotone is good because many people don't hear it. However，it also has a bad influence on their study if students use it in class.”

    People in New Zealand have a very special way of greeting(问候) people. It's called Hongi(碰鼻礼).

    When people meet, they always greet each other by pressing one's nose against another's nose. When a visitor is greeted in this way, people there won't see the person as a visitor any more, but one of the people of the land. Of course, during the visitor's stay, he has to share all the duties(职责).

    At meetings or important ceremonies(典礼) people always greet in this way. And it's just like the handshake in our country.

Sixteen is a special age in the United States. There's often a special celebration for a girl's 16th birthday—a big party called Sweet-16. It is like a wedding reception(结婚晚宴) in the number of guests and gifts handed out.

    About a month before the party, the girl's family sends out invitations to the guests. They must buy a special present for the birthday girl and the girl guests find good dresses to wear. A sweet-16 present usually costs $40 to $60. This is about $20 more than the usual-cost of a birthday present.

    The party itself is not held at someone's house. The hostess rents(租赁) a reception hall for the event. Food, cake and a DJ are provided. Around 6'clock, guests arrive and meet the birthday girl. Then the girl and her father have a special father-daughter dance. After that, guests dance for about 30 to 45 minutes.

    Then there is the most important part of the Sweet-16 party, the candle-lighting ceremony.

    The sweet-16 hostess stands behind 16 unlit(未点燃的) candles and dedicates(献给) each candle to her friends, family, and anything that she feels is important to her. A lot of crying and hugging goes on at this time.

    Afterwards, people sit and eat. Most guests begin leaving around 11 o'clock.

    This school year, I have been to two Sweet-16s. I am one of the youngest students in my grade (My birthday is in December). I'll have to wait another year before I can have my own special Sweet-16 party. I can't wait for it!

    Before you go to another country it is a great help if you know the language and some of the customs(风俗)of the country. When people meet each other for the first time in Britain, they say" How do you do?" and shake hands (握手). Usually they do not shake hands when they just meet or say goodbye. But they shake hands after they haven't met for a long time or when they will be away from each other for a long time. Last year a group of German students went to England for a holiday. Their teacher told them that the English people hardly shake hands. So when they met their English friends at the station, they kept their hands behind their backs. The English students had learned that the Germans shake hands as often as possible, so they put their hands in front and got ready to shake hands with them. It made both of them laugh.