题目

“宏微结合”——建立宏观、微观和符号之间的联系是化学学科的重要特点。 （1） 上图左表示Cl和Br的原子结构示意图。①Br的核外电子层数为。②元素Cl和Br的单质具有相似化学性质是因为。 （2） 上图右表示水、二氧化碳和氧气的转化关系图。①从宏观角度看，上图右中三种物质的组成中都含有的元素是。从微观角度看，图2中三种物质都是由(选填“分子”“原子”或“离子”)直接构成的。②写出上图右中c对应的化学方程式：。乙醇作 Students at Empire High School started class with no text books－but it wasn’t because of money problems. Instead, the school gave iBooks－laptop computers to each of its 340 students, becoming one of the first US public schools to stop printed textbooks.School officials believe that the electronic materials will make students enjoy learning more. Empire High School was designed to have a textbook-free environment.Students at Empire High School get the materials over the school’s Internet network. The school has a central control system that limits what can be downloaded(下载) at the school.“Students can hand in homework online. We have a web program that helps to check if you copy from others,” the headmaster Baker said. In addition to offering up-to-date information, teachers can make the lessons more enjoyable. For example, lessons in history can include links to a person’s daily life, his ideas, his discovery, and so on. Social studies teacher Jeremy Gypton said the change was easier than expected. Gypton said he assigned reading based on websites, used online groups and message boards to keep the students connected. And he also asked them to comment（评论）on each other’s work. Julian Tarazon, a new student, said that it was kind of hard at first, because you had to put things in folders(文件夹). But after a couple of days, you got used to it. Another student Morgan Northcutt said the computer system had made it easier to do homework.The school isn’t completely paperless, however. It has a library, and students can read books in it.“We’re not trying to get rid of books,” Baker said. “We love books.”1.The students at Empire High School will study in class without ___________ this year.A. text messagesB. printed textbooksC. reading materialsD. electric machines2.The teachers at Empire High School began to use iBooks because they___________. A. had money problemsB. had limited networkC. wanted to improve their teachingD. wanted a web program3.A central control system can help to control __________.A. how much to downloadB. what to downloadC. how to downloadD. why to download4.The underlined word “assigned” probably means “___________”.A. 说明B）完成C. 转让D）布置5.The biggest advantage of the homework online is that___________.A. students can do it anytimeB. information online is available C. there is a lot of reading based on websitesD. it provides a platform for students to share ideas6. The best title of the passage might be “___________”.A. High School uses iBooks instead of textbooks B. Don’t try to get rid of booksC. Learning without textbooks is harderD. Doing homework online