题目

1、.提醒年轻人网上慎重交友，很有必要。 Its necessary to warn the young people not to_______ online carelessly. 2、不要抱怨学校，你们可以解决这些问题. Don't complain about the school. You can_________ these problems. 3、必须采取措施来阻止此类事故发生 _______he done to stop this kind of accident from happening. 4、人们称赞这部根据中国历史上一个真实事件创作的歌剧 People _______of the opera which is based on the real event in Chinese history. 5、我想让老师和父母为我而自豪 I want to make my parents and teach如图，有三种卡片，其中边长为a的正方形卡片1张，边长分别为a、b的矩形卡片6张，边长为b的正方形卡片9张．用这16张卡片拼成一个正方形，则这个正方形的边长为    ．