在电视信号的发射和接收过程中，把图象变成电信号是由下面哪个设备完成的（　　）

完型填空
      Books are our greatest friends. They 1us stories of every country in the world. They give us all kinds of 2 . Life is short. One can not know and see 3 in the world. 4 the help of books, one is able to know what happened thousands of years ago and 5 is happening in every part of the world now. Books give us not only knowledge 6  pleasure. Reading good books is the best way of7    our free time. And many beautiful stories for children are 8and full of wisdom(智慧).
    All the great men 9 books. Knowledge from books helps them to succeed, because books are the source(源泉)of knowledge and knowledge is the source of  10 .

读史有感
“整个树林被削平得像割去谷穗的田地，所有覆盖物弹痕累累……到处都是残骸、击破的战车，碎成一块一块的尸体，击毁的大炮，几个月都是如此。”
                                                                                                                              ——来自一战的报道
请回答：
（1）上述场景反映的是哪次战役？
（2）一战的导火线是什么？一战的起止时间是什么？
（3）大战爆发前形成了哪两大军事集团？其中哪个国家在大战爆发后参加到对方作战？
（4）战争是残酷的，带来巨大的灾难，对此你有何感悟，设计一条宣传标语。