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.”
【小题1】Mosquitotone works because ________.

One day, a teacher was speaking to a group of students about how to manage time. He gave such an interesting example that his students would never   1  .
He put a wide-mouth jar (罐子) on the table. Then he    2  some rocks and carefully placed them into the jar, one at a time. When  3  rocks would fit inside, he   4  , “Is this jar full?”
Everyone in class shouted, “Yes.” “Really?” The teacher pulled out a bag of small stones. He put   5  small stones in and shook the jar. The small stones went   6  into the spaces between the big rocks. He then asked the group   7  , “Is this jar full?”
“Probably not,” one of them answered. “Good!” the teacher replied. He brought out a box of sand and   8  some sand into the jar and it went between the rocks and small stones. Again he asked the   9  question, “Is this jar full?
“No,” the class shouted. Once more the teacher said, “Good.” He poured a cup of water into the jar   10  it was full. The he asked, “What is the point here?” One student   11  his hand and said, “The point is that if you try really hard, you can   12  put more things in.”
“No,” the teacher replied, “that’s not the  13  . What I want to tell you is that if you don’t put the big rocks in first, you will never get others in at all.   14  are the ‘big rocks’ in your life? Time with your friends, your education or your dreams? Remember to put the  15  in first, or you’ll never get others in at all.?”

Are you nervous when you stand in front of the public? Are you afraid to make a speech?
Li Jun, a middle school boy, felt shy when he was making a speech the other day. Li had thought it would be quite easy to speak in front of   1  classmates.
"I was wrong. It was very different and much  2  than talking to my classmates during playtime," Li said. "I tried, but it was really difficult to speak. I felt like a mute (哑巴) and wanted to leave the classroom   3  "
Li is not alone. Many middle school students now have the same   4  : they can talk about their ideas freely   5  their best friends after class, but can't speak in public. According to Zhou Hong, a teacher from a university, the main reason is that schools in China pay more attention to writing instead of  6 .
Zhou hopes schools can give students more chances to open their   7 , such as speech competitions, English corners and class discussions. Students can join in any one they want to. 8  he also gives some advice to students. "During your free time you should  9  more. When you're speaking in public, take it easy. Just imagine you're talking to nobody and speak up your ideas clearly," Zhou said. "That   10  a fine public speech and you'll feel confident. "