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)”.

    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 someone of 20 or older can't.

    But sometimes, people over 20 can hear the ringtone. One British student's phone uses mosquitotone. In class, the student's phone rang. The 22-year-old 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(不公平的) 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. You'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（影响） on their study if students use it in class. ”

    Tigers are the largest wild cats in the world. They usually go out to hunt for food when it is dark. And they hunt alone most of time. When a tiger sees an animal, it moves quickly and then jumps on the animal to kill it. Sometimes it can take the tiger several days to finish eating its food. When the tiger is full, it will cover the dead animal with leaves. Later, when the tiger is hungry again, it comes back to eat some more.

    Tigers are different from others in the cat family. They like water and often jump into rivers to swim. Some tigers live in very cold places-in North Korea, Russia and China. Other tigers live in warmer places-in India and parts of Southeast Asia.

    But now all tigers are in danger. Some people kill tigers to use their skins for clothes, and their bodies for medicine. There is also less land for tigers to live on.

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The summer vacation is on the way! Spend time on your mobile phones? Play computer games day and night? Why don't you join one of the following clubs to develop your new interests and make your vacation more colorful? 

On very cold winter days, a group of Japanese children traveled a long way and arrived at a small island where nobody lived. After setting up a camp, they caught fish in the sea, and walked on the snow to find firewood, wild fruit and fresh water. Then they made a fire to do some cooking. They were not homeless children or modern Robinson (鲁滨逊). They were all pupils from a primary school and campers of special"hardship（苦难）camp".

Every year primary and middle schools in Japan organize such camps to train the children's spirit of bearing hardships. Such places like thick forests and far-off（遥远的）mountains are often chosen as camp places.

The Japanese education circles (教育界) usually think it necessary to give children chances of suffering（经历）hardships. Children in Japan now may hardly find times of hardships, because of the rapid growth of national economy（经济）and improvement in people's living conditions. The experts（专家）think that such hardship camps can help children learn to live and develop in the struggle against nature.

It's said that such hardship camps are warmly accepted by both Japanese school children and their parents.