题目

雷达可用于飞机导航，也可用来监测飞机的飞行，其工作原理如图所示，假设某时刻雷达向飞机发射电磁波，电磁波遇到飞机经反射后又被雷达接收，整个过程用时52.4μs．已知电磁波的速度为3.0×108m/s，则飞机离雷达站的距离是m． 答案：【1】78606．Tomorrow's World Book Day has inspired a slew of literary events throughout the capital．Xing Yi and Liu Zhihua report．As World Book Day，April 23，approaches，various reading events are being held by government agencies，libraries and bookstores throughout the capital．At the launch of the 5th Beijing Reading Season in Great Canal Park in Tongzhou district on Saturday night，81-year-old Yin Zhiguang，head of Beijing Elocution Troupe，led the audience in reciting a poem．Activities focusing on different readerships will highlight World Book Day in bookstores throughout Beijing，such as picture book sharing for children in Xidan Book Building，conversations with musicians and authors for young people in Sanlian Bookstore，talks with diplomats for people interested in international affairs in Wangfujing Xinhua bookstore，and a 12-hour late-night reading marathon for night owls at One-Way Space bookstore．Recently，we conducted a survey about how many extra-curricular books students read per year．On average，each student read 5.34books，which is definitely not adequate compared with their counterparts from the Western countries．It is upsetting to see the outcome．When asked what students in our school do in their spare time，they claim that they tend to watch TV and surf the Internet，for they can have great fun．Some students even complain that they are forced to attend some extra make-up classes so that they have no time to play，not to mention reading books．School authority is planning to launch a campaign to encourage students to read more extra-curricular books．写作内容1．用30个左右词概括上文的主要内容．2．分析学生课外阅读量不足的原因（至少两点）．3．谈谈读书的好处（至少两点）； 以及你对增加课外阅读量建议（至少两点）．写作要求1．作文中可以参照阅读材料的内容，但不得直接引用原文中的句子．2．作文中不得出现真实姓名和学校名称．With World Book Day drawing，various activities are held in Beijing to highlight the importance of book reading．But a recent survey shows students prefer to watch TV or surf the Internet rather than read books．The survey sets me thinking why fewer students choose to read books in their spare time．There are some reasons accounting for this phenomenon．First of all，most students are burdened with too much homework．Still others haven't formed a habit of reading．They would rather spend their spare time on TV or the Internet for fun．However，reading has many benefits．Through reading we can learn more about the world．Besides，it can help us think better．Last but not least，reading can make our life more colourful．I think teachers are supposed to limit the amount of our homework so that we can have more time to read．For another，it's a good idea to form reading clubs and learn from each other．．