快下课了，张老师转向黑板，写下了一串阿拉伯数字。同学们面面相觑，不知道是什么意思。张老师说：“这是我的QQ号，同学们可以加我，有事请留言。”大家先是愕然，接着大笑，进而掌声雷动。张老师和学生QQ聊天是在新课改浪潮中更新观念、重新审视师生关系的一个具体行动。

某单位有工程师6人，技术员12人，技工18人，要从这些人中抽取一个容量为n的样本．如果采用系统抽样和分层抽样方法抽取，不用剔除个体；如果样本容量增加一个，则在采用系统抽样时，需要在总体中先剔除1个个体，求样本容量n．

摩擦起电的原因是 ____从一个物体转移到另一个物体，用丝绸摩擦过的玻璃棒，玻璃棒带 ____电．

    At East China University of Science and Technology, students will get a coupon（优惠券） if they eat up their food. Students can collect coupons and exchange them for small gifts, such as books, magazines, mobile phone covers and hand warmers.

    “It's been such a surprise”, said Liang zhaoyun,19, a student at the university in Shanghai. It has given us one more motivation to finish our food.”

    The measure is part of a national 'eat—up' campaign(运动) which is organized by students to deal with food waste on campuses.

    Why only on campuses, you might ask. Because according to a report by Xinhua News Agency, students waste twice as much food as the national average.

    The campaign on campus food waste is receiving attention across the country.

    The aim of the campaign is not only to encourage students to finish their food. We hope it can also encourage students to choose a more environment–friendly and healthy lifestyle,” said Tao Siliang, secretary(秘书) of the Youth League Committee at Shanghai University.

    But some school food is poorly prepared, so students do not like to finish it all. Some schools have taken notice of this and they are taking measures to improve it.

    “I'm glad that we've reduced food waste since the ‘eat—up' campaign began. But if we call on students to waste less food, we should also improve the service and food standard on campuses.” said Tao.

照样子改写句子。

例1：大王不能说齐国没有人。

大王怎么能说齐国没有人呢？

这里的风景这么美，真叫人流连忘返。

反问句：____