A:当物距小于焦距时,凸透镜成正立、放大的实像
B:照相机是利用凸透镜成倒立、缩小的实像原理制成的
C:幻灯机是利用当物距大于2焦距时凸透镜成倒立、放大的实像的原理制成的
D:集邮爱好者观察邮票用时若一时找不到放大镜,可以用老花镜代替
一些城市通过发布“雷人标语”来纠正城市不文明现象,这实质上是一种文明的困境,是一种最无奈的做法。根除城市顽疾,关键在于____。而市民文明习惯的养成,不会一蹴而就,更不可能一劳永逸,而是____,需要长期循序渐进地宣传教育、公民自律和法规完善。尤为重要的是,需要通过文明的、市民能够接受的方式,来唤起全社会共同参与。因此,不妨多注重“标语文化”,将警示语过于严厉、刻板的面孔变一变,改用优美、温馨的语言进行表达,或许会____。
根据句意和汉语注释,写出单词的正确形式。(1)Our English teacher has offered us some useful ____ (建议). I think it will help us a lot in our English study.(2)Here are two ____ (音乐会) tickets for you.(3)Daniel ____ (不愿) to accept my books ,which made me very sad.(4)____ (比较) this new TV set with the old one, you will see which is better.
On weekdays, David gets up at 6:30.He has breakfast at seven and then he goes to school by bus. He gets there at 7:15. He doesn't like to be late. Classes begin at 8:00. He has lunch at twelve at school. He goes home at 5:30 in the afternoon. On weekends, he gets up at about 8:00 and makes breakfast for his family. His parents like him very much.