阅读理解。 Mobile phones have become a problem for middle schools. Some middle schools in Australia have prevented students from carrying mobile phone during school hours. Mobile phone use among children has become a problem for the school this year. Several children have got mobile phones as Christmas gifts, and more students will want them. Mary Bluett, an official, said mobile phone use is a distraction (伤心的事) to students during school hours and it also gives teachers so much trouble in their classrooms. Teachers were also saying that sometimes students might use phone messages to cheat during exams. She said some schools had tried not to let students use mobile phones at school. Some parents felt unhappy because they couldn't get in touch with their children. Many teachers said students should not have mobile phones at school, but if there was a good reason, they could leave their phones at school offices. They also said there were many reasons why the students should not have mobile phones at school. They were easy to lose and were a distraction from studies. Many people say that they understood why parents would want their children to have mobile phones, but they think schools should let the students know when they can use their mobile phones. 1. Middle schools are prevented from carrying mobile phones _____. [     ] A. because they often talk with their friends B. when they are free from homework C. when they are at school D. because they cheat in exams 2. Some children get mobile phones _____. [     ] A. by telling lies to their parents B. by making trouble in class C. from their parents and friends D. from some mobile phone users 3. Which of the following statements is true? [     ] A. No school in Australia has done anything about the mobile phone use among students. B. Teachers don't allow the students to leave their mobile phones at school offices. C. Some students had their mobile phones stolen at school. D. Parents give their children mobile phones for no good reason. 4. It is implied (暗含) in the passage that _____. [     ] A. students shouldn't have mobile phones at school except for some special reasons B. it is impossible to stop students from using mobile phone at school C. some parents felt unhappy because they couldn't use their phones at school D. parents should teach their children how to use mobile phones during school hours