题目

Mobile phone has become a problem for middle schools. Some middle schools in Australia have banned(禁止) students from carrying mobile phones during school hours. Mobil phone use among children has become a problem for the school this year. Several children have got mobile phones as Christmas gifts, teachers said mobile phone use is a distraction(娱乐) 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 to ban mobile ph释放核能的方式有________和________两种，太阳内部和氢弹都是通过_____释放核能的。